What eye color will be dominant? Inheritance of eye color in humans. Mechanisms of inheritance of eye color in humans

To answer the question The gene for brown eyes is considered dominant. Does he always win if the other parent's eyes are not brown? given by the author old-timer the best answer is 3:1, unless I forgot the arithmetic. That is, such parents will have three children with brown eyes, and the fourth with blue eyes. But if the brown-eyed one himself has ancestors with different colors eye, the likelihood that a child will have blue eyes increases MAYBE....

Reply from Alina[guru]
No, not always. Mom's eyes are brown, father's are blue. I have brown ones, my sister has blue ones, and my second sister has green ones. My son's father has brown eyes, that is, both parents have brown eyes, but my son’s eye color is green.

Reply from Neurosis[guru]
no, in my opinion this is nonsense... if he doesn’t always win, why is he dominant?

Reply from Accomplice[newbie]
No, no and no! My mom and dad are brown-eyed, and I Blue eyes! My husband has brown ones, and our children have blue ones! Here!

Reply from Alexey 11[guru]
unfortunately this is so

Reply from Larisa Pavlova[guru]
no, not always, my eyes are gray and my husband’s are brown, our daughter’s eyes are gray like mine

Reply from EYES GREEN KNEES BLUE[guru]
In our case, the brown one won))) as you know, I have green eyes))

Reply from Diver[active]
not always but often

Reply from N.[guru]
We went through this at school, there are calculations on the power of probability, open the textbook "General Biology".)

Reply from Yatyana[guru]
I have brown eyes, my husband has blue eyes, but my daughter still has blue eyes like her husband, which means that brown ones do not always dominate

Reply from Olka[newbie]
Not always!! ! A child does not necessarily inherit a dominant gene, but can also inherit a recessive one if previous generations had it). And we have brown-eyed parents and a blue-eyed daughter))

Reply from Anna Zilina[active]
won against us. My husband has brown eyes, my daughter also has brown eyes.

Reply from Kisa[expert]
Biology textbook for 9th grade. No, not always.

Reply from ~Give me the Crown, Darling~[guru]
not always. my father has brown ones, and my mother has green ones

Reply from MarS[guru]
My wife and I have brown eyes, and my daughter has blue eyes, like her grandfather’s. AND.. . such a paradox. Until I was seven years old, my eyes were blue, and then they suddenly turned brown, that is, they became caried-dominated:.... (my father had blue eyes, my mother had brown eyes).

Reply from Irina I[guru]
Not always.

Reply from Hyperv strat[newbie]
We cannot isolate all alleles. Compared to all common alleles, it wins. But what if there is such a gray-brown-crimson color that its allele is more dominant? It's impossible to say for sure.

Reply from Vita[guru]
not always

Reply from Lyubov Semyonova[guru]
My eyes are green, my husband's are brown, and my daughter's are blue.

Reply from [email protected] [guru]
No. I have brown eyes, but our dad has blue eyes and our daughter has blue eyes.

In humans, the gene for brown eyes is dominant over the gene causing blue eyes. A blue-eyed man, one of whose parents had brown eyes,

married a brown-eyed woman whose father had brown eyes and whose mother had blue eyes. What kind of offspring can be expected from this marriage?

In humans, the gene for brown eyes is dominant over the gene causing blue eyes. A blue-eyed man, one of the parents who had brown eyes, got married

on a brown-eyed woman whose father had brown eyes and his mother had blue eyes. What kind of offspring can be expected from this marriage?

No. 2. What kind of offspring can you expect?

from crossing a cow and a bull,
heterozygous for coat color?
Problem No. 3. Guinea pigs have frizzy hair
wool is determined by a dominant gene, and
smooth - recessive.
1. Crossing two curled pigs between
produced 39 individuals with shaggy fur and
11 smooth-haired animals. How many among
individuals having a dominant phenotype,
must be homozygous for this
sign?
2. Guinea pig with shaggy fur
crossed with an individual with a smooth
wool, gave birth to 28 frizzy and 26
smooth-haired offspring. Define
genotypes of parents and offspring.
Task No. 4. An offspring was obtained at the fur farm
in 225 minks. Of these, 167 animals have
brown fur and 58 bluish-gray minks
coloring. Determine the genotypes of the original
forms, if it is known that the gene is brown
coloring dominates the gene,
defining bluish-gray color
wool
Problem No. 5. A person has a gene for brown eyes
dominates the gene causing
Blue eyes. Blue-eyed man, one
of whose parents had brown eyes,
married a brown-eyed woman who
the father had brown eyes, and the mother had blue eyes.
What kind of offspring can be expected from this
marriage?
Problem No. 6. Albinism is inherited in
human as a recessive trait. In the family
where one of the spouses is an albino, and the other has
pigmented hair, have two children.
One child is albino, the other is
dyed hair. What is the probability
birth of the next albino child?
Problems on di- and polyhybrid crossing
Problem No. 8. At a large cattle gene
polledness dominates the horned gene, and
gene for black coat color - above the gene
red color. Both pairs of genes are located
in different pairs of chromosomes.
1. What will the calves turn out to be like if they are crossed?
heterozygous for both pairs
signs of a bull and a cow?
2. What kind of offspring should be expected from
crossing a black polled bull,
heterozygous for both pairs of traits,
with a red horned cow?
Problem No. 9. Dogs have black fur
dominates the coffee, and the short coat
- over the long one. Both pairs of genes are in
different chromosomes.
1. What percentage of black shorthairs
puppies can be expected from crossing two
individuals heterozygous for both traits?
2. The hunter bought a black dog with a short
wool and wants to be sure that it is not
carries genes long hair coffee color.
Which partner according to phenotype and genotype do you need?
select for crossing to check
genotype of the purchased dog?
Problem No. 10. A person has a gene for brown eyes
dominates the gene that determines
development of blue eye color, and the gene
conditioning the ability to better master
right hand, predominates over the gene,
determining the development of left-handedness. Both
pairs of genes are located in different
chromosomes. What kind of children can they be if
Are their parents heterozygous?

In humans, the gene for normal hearing (B) dominates over the gene for deafness and is located in the autosome; the gene for color blindness (color blindness - d) is recessive and linked to the X chromosome. In a family where the mother suffered from deafness but had normal color vision, and the father had normal hearing (homozygous) and was color blind, a color blind girl with normal hearing was born. Make a diagram for solving the problem. Determine the genotypes of the parents, daughters, possible genotypes of the children and the likelihood of the future birth of color-blind children with normal hearing and deaf children in this school.

Answer

B – normal hearing, b – deafness.

The mother is deaf, but has normal color vision bbX D X _ .
Father with normal hearing (homozygous), color blind BBX d Y.

The colorblind girl X d X d received one X d from her father and the second from her mother, therefore the mother is bbX D X d .

P	bbX D X d	x	BBX d Y
G	bX D		BXd
	bX d		BY
F1	BbX D X d		BbX D Y	BbX d X d	BbX d Y
	girls from normal hearing and vision		boys from normal hearing and vision	girls from normal hearing, colorblind	boys from normal hearing, colorblind

Daughter BbX d X d . Probability of having colorblind children = 2/4 (50%). All of them will have normal hearing, the probability of being born deaf = 0%.

In humans, the gene for brown eyes is dominant over blue eye (A), and the gene for color blindness is recessive (color blindness - d) and linked to the X chromosome. A brown-eyed woman with normal vision, whose father had blue eyes and suffered color blindness, marries a blue-eyed man with normal vision. Make a diagram for solving the problem. Determine the genotypes of the parents and possible offspring, the likelihood of having color-blind children with brown eyes and their gender in this family.

Answer

A – brown eyes, and – blue eyes.
X D – normal vision, X d – color blindness.

Brown-eyed woman with normal vision A_X D X _ .
The woman's father is aaX d Y, he could only give his daughter aX d, therefore, the brown-eyed woman is AaX D X d.
The woman's husband is aaX D Y.

P AaX D X d x aaX D Y

The probability of having a colorblind child with brown eyes is 1/8, (12.5%) and it is a boy.

One form of anemia (blood disease) is inherited as an autosomal dominant trait. In homozygotes this disease leads to death, in heterozygotes it manifests itself in a mild form. A woman with normal vision, but a mild form of anemia, gave birth to two sons from a healthy (by blood) color-blind man - the first, suffering from a mild form of anemia and color blindness, and the second, completely healthy. Determine the genotypes of the parents, sick and healthy sons. What is the probability of having the next son without anomalies?

Answer

AA – death, Aa – anemia, aa – normal.
X D – normal vision, X d – color blindness.

A woman with normal vision, but mild form anemia AaX D X _ .
A healthy blood color-blind man aaX d Y.
The first child is AaX d Y, the second child is aaX D Y.

The first child received Y from his father, therefore, he received X d from his mother, therefore, his mother AaX D X d.

P AaX D X d x aaX d Y

The probability of having the next son without anomalies is 1/8 (12.5%).

Deafness is an autosomal trait; color blindness is a gender-linked trait. In the marriage of healthy parents, a child was born who was deaf and color blind. Make a diagram for solving the problem. Determine the genotypes of the parents and the child, its gender, genotypes and phenotypes of possible offspring, the likelihood of having children with both anomalies. What laws of heredity are manifested in this case? Justify your answer.

Answer

Healthy parents gave birth to a sick child, therefore, deafness and color blindness are recessive traits.

A - normal. hearing, a - deafness
X D - normal. vision, X d - color blindness.

The child has aa, the parents are healthy, therefore they are Aa.
The father is healthy, therefore he is X D Y. If the child were a girl, then she would have received X D from her father and would not be color blind. Consequently, the child is a boy and received the color blindness gene from his mother. The mother is healthy, therefore fire X D X d .

P AaX D X d x AaX D Y

	AX D	AY	aX D	aY
AX D	AAX D X D normal hearing normal vision girl	AAX D Y normal hearing normal vision boy	AaX D X D normal hearing normal vision girl	AaX D Y normal hearing normal vision boy
AX d	AAX d X D normal hearing normal vision girl	AAX d Y normal hearing colorblind boy	AaX d X D normal hearing normal vision girl	AaX d Y normal hearing colorblind boy
aX D	AaX D X D normal hearing normal vision girl	AaX D Y normal hearing normal vision boy	aaX D X D deafness normal vision girl	aaX D Y deafness normal vision boy
aX d	AaX d X D normal hearing normal vision girl	AaX d Y normal hearing colorblind boy	aaX d X D deafness normal vision girl	aaX d Y deafness color blindness boy

The probability of having a child with two anomalies is 1/16 (6.25%).

In this case, Medel's third law (the law of independent inheritance) appeared.

The shape of the wings in Drosophila is an autosomal gene, the gene for eye color is located on the X chromosome. The male sex is heterogametic in Drosophila. When female fruit flies with normal wings and red eyes were crossed and males with reduced wings and white eyes, all offspring had normal wings and red eyes. The resulting F1 males were crossed with the original parent female. Make a diagram for solving the problem. Determine the genotypes and phenotypes of parents and offspring in two crosses. What laws of heredity appear in two crosses?

Answer

In the first generation, uniform offspring were obtained (Mendel's first law), therefore the parents were homozygotes, F1 were heterozygotes, and heterozygotes showed dominant genes.

A - normal wings, a - reduced wings
B - red eyes, b - white eyes

P AAX B X B x aaX b Y
F1 AaX B X b , AaX B Y

AaX B Y x AAX B X B

	AX B	aX B	AY	aY
AX B	AAX B X B	AaX B X B	AAX B Y	AaX B Y

All offspring turned out to have normal wings and red eyes. In the second crossing, Mendel's third law (the law of independent inheritance) appeared.

In Drosophila, the heterogametic sex is male. Drosophila females with a gray body, red eyes and males with a black body, white eyes were crossed, all the offspring were uniform in body and eye color. In the second crossing of Drosophila females with a black body, white eyes and males with a gray body, red eyes, the offspring were females with a gray body, red eyes and males with a gray body, white eyes. Draw up crossing schemes, determine the genotypes and phenotypes of the parents, offspring in two crosses and the sex of the offspring in the first cross. Explain why the characteristics split in the second crossing.

Answer

A - gray body, a - black body
X E - red eyes, X E - white eyes

Since in the first crossing all the offspring were uniform, therefore, homozygotes were crossed:
P AA X E X E x aaX e Y
F1 AaX E X e, AaX E Y (all with gray body and red eyes)

Second crossing:
P aa X e X e x AAX E Y
F1 AaX e X E, AaX e Y (females with a gray body and red eyes, males with a gray body and white eyes)

The splitting of characters in the second generation occurred because the eye color trait is linked to the X chromosome, and males receive the X chromosome only from the mother.

In humans, the inheritance of albinism is not sex-linked (A - the presence of melanin in skin cells, and - the absence of melanin in skin cells - albinism), and hemophilia is sex-linked (X H - normal blood clotting, X h - hemophilia). Determine the genotypes of the parents, as well as the possible genotypes, sex and phenotypes of children from the marriage of a dihomozygous woman, normal for both alleles, and an albino man with hemophilia. Make a diagram for solving the problem.

Answer

A is normal, a is albinism.
X H - normal, X h - hemophilia.

Woman ААХ Н Х Н, man ааХ Н Х h.

Wing shape in Drosophila is an autosomal gene; the gene for eye size is located on the X chromosome. The male sex is heterogametic in Drosophila. When two fruit flies with normal wings and normal eyes were crossed, the offspring produced a male with curled wings and small eyes. This male was crossed with the parent. Make a diagram for solving the problem. Determine the genotypes of the parents and the resulting F1 male, and the genotypes and phenotypes of the F2 offspring. What proportion of females from the total number of offspring in the second cross is phenotypically similar to the parent female? Determine their genotypes.

Answer

Since crossing two fruit flies with normal wings resulted in a child with curled wings, therefore A - normal wings, a - curled wings, parents Aa x Aa, child aa.

The gene for eye size is linked to the X chromosome, therefore, the male with small eyes received Y from his father, and the gene for small eyes from his mother, but the mother herself had normal eyes, therefore, she was a heterozygote. X B - normal eyes, X b - small eyes, mother X B X b, father X B Y, child X b Y.

F1 AaX B X b x aaX b Y

Phenotypically similar to the parent female will be F2 AaX B X b, their 1/8 (12.5%) of the total number of offspring.

ANSWER: The offspring always receives only one gene from the alleles from their parents. Since a blue-eyed girl was born, it means that she received one blue-eyed gene from her mother, i.e. she was heterozygous for this trait and her genotype was Aa. The genotype of the blue-eyed father is aa (a recessive trait appears only in the homozygous state)

GAMES (G) A, a a

ANSWER: Aa and aa; probability of having brown-eyed children is 50%

1. In humans, non-red hair is dominant over red hair. Father and mother are heterozygous brown. They have eight children. How many of them might be redheads? Is there a clear answer to the question?

ANSWER: Since the parents are heterozygous, they carry one gene for red hair. Theoretically, they can have 2 red-haired children (25%). But the meeting of gametes during fertilization occurs by chance and therefore in a given family all non-red or all red-haired people can be born.

1. The black color of the fur of minks dominates over the blue. How to prove the purebred nature of two black minks purchased by a fur farm?

ANSWER: Both heterozygous and homozygous individuals can have black coloration. But purebred individuals are homozygous and do not produce segregation in the offspring. To find out the genotypes of purchased minks, you need to cross them with blue minks. If blue minks appeared in the offspring, it means that the mink was not purebred, that is, heterozygous (Aa); if there is no cleavage - homozygous (AA).

1. Brown-eyed right-hander married a blue-eyed, left-handed man. They gave birth to a blue-eyed left-hander. Determine the mother's genotype (brown eyes and right-handedness are dominant).

ANSWER: Since their child exhibited recessive genes for both traits, he received one of them from each parent, i.e. the mother was heterozygous for two traits and her genotype was AaBb.

1. Black coat color (A) dominates over white coat (a), and shaggy coat (B) dominates over smooth coat (c). What phenotypic cleavage should be expected from crossing two rabbits heterozygous for two traits?

ANSWER: Since the parents are diheterozygous, they have the AaBb genotype, and with such a crossing, the offspring exhibit phenotypic splitting - 9: 3: 3: 1.

1. What is the probability of having a blue-eyed (a), fair-haired (c) child from the marriage of a blue-eyed, dark-haired father with the aaBb genotype and a brown-eyed, fair-haired mother with the Aabv genotype?

ANSWER: R Aavv X aaVv

GAMETES (G) Av, av aB, av

AaVv Aavv aaVv aavv

K.t. k.s g.t. g.s.

ANSWER: 25%.

1. When crossing two varieties of tomato with red spherical and yellow pear-shaped fruits in the first generation, all the fruits are spherical and red. Determine the genotypes of parents, first-generation hybrids, and the ratio of second-generation phenotypes.

ANSWER:

1) genotypes of the parents: red spherical fruits - AABB,
yellow pear-shaped fruits – aabb

2) genotypes F 1: red spherical AaBb

3) ratio of phenotypes F 2:

9 – red spherical
3 – red pear-shaped
3 – yellow spherical
1 – yellow pear-shaped

1. A blue-eyed man, both of whose parents are brown-eyed, married a brown-eyed woman whose mother is blue-eyed and whose father is brown-eyed. From the marriage a blue-eyed son was born. Make a pedigree and indicate the genotypes of all relatives.

ANSWER: 1) First, we draw up a pedigree diagram and sign the phenotypes.

2) Then, we write down the genotypes of individuals who have a recessive trait, i.e. homozygous for this gene.

3) These individuals transmit (parents) or receive (children) one recessive gene, so we record these genes in the genotype of children or parents.

4) In persons with a dominant trait, we write down the genotype first one dominant gene And according to the scheme, their homozygosity or heterozygosity will be revealed

.

1. What blood types are possible in children if the mother has the first blood group and the father has the fourth?

SOLUTION: The first group is determined by the OO genotype, the fourth - AB. Alleles A and B are dominant to allele O.

2nd group 3rd group

ANSWER: Children will have 2 and 3 blood groups.

1. The genes for coat color in cats are located on the X chromosome. Black coloring is determined by the gene X B red - X b, heterozygotes have a tortoiseshell color. One tortoiseshell and one black kitten were born from a black cat and a ginger cat. Determine the genotypes of parents and offspring, the possible sex of kittens. Solution:

P X B X B x X b Y

F 1 X B Y X B X b

ANSWER: genotype of a black cat X B X B, genotype of a red cat - X b Y, genotypes of kittens: tortoiseshell - X B X b

Black - X V Y, gender of kittens: tortoiseshell - female, black - male.

1. Two black female mice were crossed with a brown male. The first female gave birth to 20 black and 17 brown offspring in several litters, and the second female gave birth to 33 black offspring. Determine the genotypes of parents and offspring, explain the answer.

ANSWER: Since there was no splitting in the offspring of the second black female, all the offspring were black, which means that black color is dominant and the genotype of the male is aa, the genotype of the second female is AA. In the offspring of the first female, a 1:1 split is observed, which means that the genotype of the first female is Aa. The genotypes of the offspring from the first female are Aa (20 black) and aa (17 brown), the genotype of the offspring from the second female is Aa (uniformity - 33 black).

1. In a family where the parents have normal color vision, the son is color blind. Normal genes color vision(D) and color blindness (d) are located on the X chromosomes. Determine the genotypes of the parents, the colorblind son and the likelihood of having children who are carriers of the colorblind gene.

ANSWER: Genotypes of parents: mother – X D X d, father X D Y; the genotype of the son is colorblind -X dU; the probability of being born as carriers of the color blindness gene (X D X d) is 25%.

1. Prove that the genotype is an integral system.

ANSWER: The genotype is an integral system, because there are interactions between allelic and non-allelic genes (dominance, codominance, complementarity, etc.), one gene can influence the development of several traits, several genes can influence the development of one trait.

1. Healthy parents have a son with hemophilia. Determine the genotypes of the parents, their son, the likelihood of having sick children and carriers of the hemophilia gene in these parents, if the hemophilia gene (h) is recessive and sex-linked.

ANSWER: genotypes of the parents: mother - X N X h, father - X H Y; son's genotype - X h Y; the probability of having sick children is 25% (sons), 25% of sons are healthy, daughters are healthy (Х Н Х H, Х Н Х h), but half of the daughters are carriers of the hemophilia gene

1. What is the essence of T. Morgan's chromosome theory of heredity?

ANSWER: Genes are located linearly on a chromosome. Genes on the same chromosome form a linkage group and are therefore inherited together. The number of linkage groups is equal to the haploid set of chromosomes. Disruption of gene linkage occurs in the process of crossing over, the frequency of which depends on the distance between genes - the greater the distance between genes, the greater the frequency of crossing over.

1. A man with normal vision married a colorblind woman (the recessive gene d is linked to the X chromosome). Determine the genotypes of the parents, the ratio of phenotypes and genotypes in the offspring.

ANSWER: Genotypes of parents: mother – X d X d, father X D Y; genotypes of the offspring: all daughters are carriers of the color blindness gene - X D X d, all sons are color blind - X d Y; the ratio of sick and healthy children is 1:1 or 50%:50%.

1. Crossed two snapdragon plants with red and white flowers. Their offspring turned out to have pink flowers. Determine the genotypes of parents, first-generation hybrids and the type of inheritance of the trait.

ANSWER: The appearance of an intermediate trait in the offspring indicates incomplete dominance of the trait. Genotypes of parental plants (P): AA and aa. Gametes: A And A. Genotypes of the first generation: Aa.

1. Using the pedigree presented in the figure, establish the nature of inheritance of the trait highlighted in black (dominant or recessive, sex-linked or unlinked), and the genotypes of children in the first and second generations.

ANSWER: 1) The trait is dominant, since it is always transmitted to offspring, and is not sex-linked, since it is transmitted equally to both daughters and sons. 2) genotypes of children in F 1 women - ahh And Ahh

Men - aa and aa. Genotypes of descendants F 2 man - Ah. Genotypes of parents: female : ahh , man Ah.

1. When crossing a tomato with a purple stem (A) and red fruits (B) and a tomato with a green stem and red fruit, 722 plants with a purple stem and red fruits and 231 plants with a purple stem and yellow fruits were obtained. Make a diagram for solving the problem. Determine the genotypes of parents, offspring in the first generation and the ratio of genotypes and phenotypes in the offspring.

ANSWER: parental genotypes: purple stem, red fruits - AABb (gametes: AB and Ab); green stem, red fruits –aaBb (gametes aB and ab); genotypes of offspring in F 1: AaBB, AaBb, Aabb; ratio of genotypes and phenotypes in F 1:
purple stem, red fruits – 1 AaBB: 2 AaBb
purple stem, yellow fruit – 1 Aabb.

1. Based on the pedigree shown in the figure, determine the nature of the manifestation of the trait (dominant, recessive), indicated in black. Determine the genotype of parents and children in the first generation.

ANSWER: 1) the trait is recessive;

2) genotypes of the parents: mother - aa, father - AA or Aa;

3) genotypes of children: heterozygous son and daughter - Aa (allowed: other genetic symbolism that does not distort the meaning of solving the problem, indicating only one of the options for the father's genotype).

1. The absence of small molars in humans is inherited as a dominant autosomal trait. Determine the possible genotypes and phenotypes of parents and offspring if one of the spouses has small molars, while the other does not have them and is heterozygous for this trait. What is the likelihood of having children with this anomaly?

ANSWER: Genotypes and phenotypes P: aa – with small molars, Aa – without small molars; genotypes and phenotypes of the offspring: Aa – without small molars, aa – with small molars; the probability of having children without small molars is 50%.

1. What underlies the combinative variability of organisms? Explain your answer.

ANSWER: Combinative variability is based on following processes:

1. crossing over leads to a change in the combination of genes in homologous chromosomes;
2. meiosis, which results in independent segregation of chromosomes into gametes;
3. random combination of gametes during fertilization.

1. Using the pedigree presented in the figure, establish the nature of inheritance of the trait highlighted in black (dominant or recessive, sex-linked or not), the genotypes of children in the first and second generation.

ANSWER:

1. the trait is dominant, not sex-linked;
2. genotypes of children of the 1st generation: daughter Aa, daughter aa, son Aa;
3. genotypes of children of the 2nd generation: daughter Aa

1 2	Symbols man woman marriage Children of the same marriage - manifestation of the trait under study

1. Based on the person’s pedigree presented in the figure, establish the nature of inheritance of the “small eyes” trait, highlighted in black (dominant or recessive, sex-linked or not). Determine the genotypes of the parents and offspring F(1, 2, 3, 4, 5).

ANSWER: 1) the trait is recessive, not sex-linked (since it is transmitted to both daughters and sons); 2) genotypes of parents: Aa x Aa; 3) genotypes of descendants in F1: 1,2- Aa; 3 – AA or Aa; 4, 5 - aa.

Standards of answers to tasks Line C1 Excellent exam 2010
1. What is the role nucleic acids in protein biosynthesis? Answer:
Answer elements: information is copied from DNA to RNA, which transfers it from the nucleus to the ribosome, mRNA. serves as a matrix for the assembly of protein molecules; tRNAs attach amino acids and deliver them to the assembly site of the protein molecule to the ribosome.
2. Ribosomes from different cells, the entire set of amino acids and identical molecules of mRNA and tRNA, created all the conditions for protein synthesis. Why will one type of protein be synthesized on different ribosomes in a test tube?
Answer: The primary structure of a protein is determined by the sequence of amino acids; The templates for protein synthesis are identical mRNA molecules, which encode the same primary protein structure.
3. The process of photosynthesis occurs intensively in the leaves of plants. Does it occur in ripe and unripe fruits? Explain your answer.
Answer elements: 1) photosynthesis occurs in unripe fruits (while they are green), since they contain chloroplasts; 2) as the chloroplast matures, they transform into chromoplasts, in which photosynthesis does not occur.
4. Why, in order to remove a tick that has attached itself to a person’s body, it must be lubricated with an oily liquid? Answer:
1) the oily liquid closes the openings of the trachea, which are the respiratory organs of ticks
2) flares die from lack of oxygen and are easily removed.
5. Explain what toothless and pearl barley feed on and why they are called “bottom filters”. Answer:
Toothless and pearl barley feed on organic particles, which, with a current of water, enter the mantle cavity and are filtered by cilia, passing through large number water, they purify it from organic and impurities and microorganisms.
6. Why is it recommended to drink salted water in the summer when you are thirsty for a long time?
Answer elements: in summer a person sweats more; excreted from the body in sweat mineral salts; salted water restores normal water-salt balance between tissues and the internal environment of the body.
7. Why are passengers recommended to suck lollipops when taking off or landing an airplane? Answer:
Answer elements: 1) a rapid change in pressure during takeoff or landing of an aircraft causes discomfort in the middle ear, where the initial pressure on eardrum lasts longer; 2) swallowing movements improve air access to the auditory (Eustachian) tube, through which the pressure in the middle ear cavity is equalized with the pressure in the environment.
8 Which plant organs are damaged by cockchafers? different stages individual development? Answer:
1) plant roots are damaged by larvae; 2) tree leaves are damaged by adult beetles.
9. Insertion into the patient’s vein large doses medicines accompanied by their dilution with physiological solution (0.9% NaCl solution). Explain why.
Answer: 1) the concentration of saline solution (0.9% NaCl solution) corresponds to the concentration of salts in the blood plasma and does not cause the death of blood cells; 2) administration of large doses of drugs without dilution can cause a sharp change in blood composition and irreversible phenomena
10. What processes maintain persistence? chemical composition human blood plasma? Answer:
Answer elements: 1) processes in buffer systems maintain the reaction of the environment (pH) at a constant level; 2) is carried out neurohumoral regulation chemical composition of plasma.
11. What is the reason for the need for iron ions to enter the human blood? Explain your answer. Answer:
Answer elements: 1) iron ions are part of the hemoglobin of erythrocytes; 2) red blood cells provide transport of oxygen and carbon dioxide.
12. In ancient India, a person suspected of a crime was offered to swallow a handful of dry rice. If he failed, guilt was considered proven. Give physiological basis this process. ,
Answer: 1) swallowing is a complex reflex act, which is accompanied by salivation and irritation of the tongue; 2) with strong excitement, salivation is sharply inhibited, the mouth becomes dry and the swallowing reflex does not occur.
13. What processes ensure the movement of water and minerals throughout the plant? Explain your answer. Answer:
1) from the root to the leaves water and minerals move through vessels due to transpiration, as a result
by which the sucking force arises; 2) the upward current in racegenia is facilitated by root pressure, which arises as a result of the constant flow of water into the root due to the difference in the concentration of substances in the cells and environment.
14. Why are owls in a forest ecosystem classified as second-order consumers, and mice as first-order consumers? Answer:
Answer elements: 1) owls feed on herbivores, therefore they are classified as second-order consumers; 2)mice eat plant foods, therefore they are classified as first-order consumers.
15. Why is the relationship between pike and perch in a river ecosystem considered competitive?
Answer elements: 1) are predators, feed on similar food; 2) live in the same body of water and need similar
living conditions mutually oppress each other
16. Why can the number of commercial herbivorous fish sharply decrease when predatory fish are destroyed in a reservoir?
Elements of the answer: 1) the destruction of predators leads to a sharp increase in the number of herbivorous fish and increased competition between them; 2) a large number of herbivorous fish contributes to a decrease in the food supply, the spread among them various diseases, this will lead to massive fish death.
17. What serves as the basis for the formation of diverse food networks in ecosystems? Answer:
1) diversity of species, the presence of producers, consumers, and decomposers among them; 2) feeding species with a variety of foods (broad food specialization).
18. Explain why beef that has not passed sanitary control is dangerous to eat undercooked or lightly cooked.
Answer elements: 1) beef meat may contain bovine tapeworm; 2) an adult worm develops from the finna in the digestive canal, and the person becomes the final host.
19. Explain why growing legumes does not require fertilizing with nitrogen fertilizers. Answer:
Answer elements: I) nodule bacteria settle on the roots of legumes; 2) they absorb nitrogen from the air and provide plants with nitrogen nutrition.
20. What is the protective role of leukocytes in the human body? Answer:
Answer elements: 1) leukocytes are capable of phagocytosis - devouring and digesting proteins, microorganisms, dead cells; 2) leukocytes take part in the production of antibodies that neutralize certain antigens.
21. Which milk, sterilized or freshly milked, will sour faster under the same conditions? Explain your answer. Answer:
Answer elements: 1) freshly milked milk will sour faster, since it contains bacteria that cause fermentation of the product; 2) when milk is sterilized, the cells and spores of lactic acid bacteria die and the milk lasts longer.
22. Why is the volume of urine excreted by the human body per day not equal to the volume of liquid drunk during the same time? Answer:
Answer elements: 1) part of the water is used by the body or formed in metabolic processes; 2) part of the water evaporates through the respiratory organs and through sweat glands.
23. Why can treating a person with antibiotics lead to intestinal dysfunction? Give at least two reasons.
Answer: 1) antibiotics kill beneficial bacteria, living in the human intestines; 2) the breakdown of fiber, water absorption and other processes are disrupted.
24. Red algae (purple algae) live at great depths. Despite this, photosynthesis occurs in their cells. Explain how photosynthesis occurs if the water column absorbs rays from the red-orange part of the spectrum.
Answer elements: 1) photosynthesis requires rays of the red and blue parts of the spectrum; 2) the cells of scarlet mushrooms contain a red pigment that absorbs rays from the blue part of the spectrum, their energy is used in the process of photosynthesis.
25. The color of the white hare’s fur changes throughout the year: in winter the hare is white, and in summer it is gray. Explain what type of variability is observed in an animal and what determines the manifestation of this characteristic.
Answer elements: 1) the hare exhibits modification (phenotypic, non-hereditary) variability;
2) the manifestation of this trait is determined by changes in environmental conditions (temperature, day length).
26. Which of the following types of fuel - natural gas, coal, nuclear energy contribute to the creation of the greenhouse effect? Explain your answer.
Answer elements: 1) natural gas and coal contribute to the creation of the greenhouse effect; 2) when they are burned, they form carbon dioxide which creates a greenhouse effect.
27. Frozen apples release a sweetish juice when thawed. What is this connected with?
1). When water freezes, it expands, thereby compromising the integrity of tissues, cells, and organelles; 2) after thawing, cell sap containing sugary substances flows out of the cell vacuoles.
28. Why is the soil in forest plantations populated with mycorrhizal fungi?
1). Trees enter into symbiosis with fungi; 2) plant roots receive additional mineral nutrition, plants tolerate unfavorable conditions more easily.
29. What is the purpose of picking plants?
1). When picking, the tip of the main root is removed, which promotes the development of lateral roots; 2) as a result, the plant nutrition area increases.
30. What is the role of chemosynthetic bacteria in ecosystems?
1). Form organic substances from inorganic ones; 2). They are classified as producers and in ecosystems they form the first link in the food chain.
31. What processes ensure the movement of water and minerals throughout the plant? Explain your answer.
Elements of the answer: 1) from the root to the leaves, water and minerals move through the vessels due to transpiration, as a result of which suction force arises; 2). the upward flow in the plant is facilitated by root pressure, which arises as a result of the constant flow of water into the root due to the difference in the concentration of substances in the cells and the environment.
32. The process of photosynthesis occurs intensively in the leaves of plants. Does it occur in ripe and unripe fruits? Explain your answer.
Answer elements: 1) photosynthesis occurs in unripe fruits (while they are green), since they contain chloroplasts; 2) as they mature, chloroplasts turn into chromoplasts, in which photosynthesis does not occur.
33. circulatory system insects is not associated with gas transport. How are they transported throughout the body of animals?
1). Gases are transported through the respiratory organs; 2). Respiratory system is represented by a network of branched tracheae, through which oxygen is delivered directly to the cells, and carbon dioxide enters the trachea from the cells.
34. What is conditioned reflex and what is its role in the life of the animal?
1), reflexes acquired by humans and animals throughout life, formed on the basis of unconditioned 2). Helps the body adapt to specific living conditions.
35. You can sometimes see a large number of earthworms on the soil surface. Explain under what meteorological conditions this occurs and why?
1). Observed after heavy rain, when earthworms move, they fill with water; 2). The oxygen content decreases, the breathing of worms in the soil becomes difficult and they migrate to the surface.