AP BIO Final part 1

a gene locus is

Location of a gene on a chromosome

In horses, black coat color is influenced by the dominant allele (B), and chestnut coat color is influenced by the recessive allele (b). Trotting gait is due to a dominant gene (T), pacing gait to the recessive allele (t). If a homozygous black trotter is crossed to a chestnut pacer, (a) What will be the phenotypes of the F1 and F2 generations? (b) Which phenotype will be the most common in the F2 generation? (c) Which genotype will be the most common in the F2 generation? (d) Which of the potential offspring will be certain to breed true?

(a) F1: black trotters F2: 9 black trotters, 3 black pacers, 3 chestnut trotters, 1 chestnut pacer (b) Black trotter (c) Bb Tt (d) bb tt, chestnut pacers

There are three alleles controlling the ABO blood types. I A and I B are codominant genes so that the combination I A I B produces the AB blood type. The third allele, i, is recessive to the other two alleles. Indicate which of these parents could produce the given child: Parents Child Yes or No (a) A ́ AB B (b) A ́ O A (c) A ́ B O (d) A ́ AB O (e) A ́ AB B (f) B ́ B O (g) AB ́ AB A

(a) Yes (b) Yes (c) Yes (d) No (e) Yes (f) Yes (g) Yes

The allele for albinism (c) is recessive to the allele for normal pigmentation (C). A normally pigmented woman whose father is an albino marries an albino man whose parents are normal. They have three children, two normal and one albino. Give the genotypes for each person listed.

-Normal pigmented woman: Cc -albino father: cc -albino man:cc -normal parents:Cc + Cc -three children, two normal Cc, 1 albino cc

a species is found to exist in one of 3 colors. Assuming an epistatic interaction, how many genes would be involved?

2

down syndrome involves trisomy ____.

21

(#26) using the accompanying illustration and the assumption that half of a plant's sperm and eggs are p and half are P, what is the chance of obtaining heterozygous offspring from this cross

25%

a women heterozygous for color blindness ( an X- linked recessive allele) marries a man with normal color vision. what is the probability that their first child (male or female) will be color blind?

25%

the probability of producing a normal child by two parents who are carriers for an autosomal recessive disorder

75%

​Consider the work Mendel did with his pea plants. Why is the study of human genetics much more difficult?

Compared to peas, humans are a difficult species on which to perform genetics. First, we have a long generation time making studies of the multiple generations difficult. Second, we produce relatively few offspring which weakens statistical analysis. Third, we can't ethically be told who to mate with so controlling crosses is difficult. Fourth, we can't self-fertilize. Fifth, many of our traits do not follow simple Mendelian inheritance patterns. The list goes on and on

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with purple flowers crossed with a tall plant with white flowers produces 3/8 tall purple, 1/8 tall white, 3/8 dwarf purple, and 1/8 dwarf white. What is the genotype of the parents?

Dd Pp x Dd pp

which of the following is TRUE of cystic fibrosis

It leads to increased bacterial lung infections.

Which statement about sex chromosomes is correct?

The X chromosome carries more genes for nonsexual traits than does the Y.

Which statement most completely describes why the pea plant was an excellent choice for Mendel's experiments?

True-breeding varieties were available, the plant can self-fertilize, and it can be cross-fertilized.

what is the sex chromosome composition of a person with Turner syndrome

XO

what is the sex chromosome composition of a person with Klinefelter syndrome?

XXY

In humans, an X-linked disorder called coloboma iridia (a fissure in the iris) is a recessive trait. A normal couple has an afflicted daughter. The husband sues the wife for divorce on the grounds of infidelity. Would you find in his favor?

Yes, the daughter would have to inherit the recessive trait from both parents and since the husband is normal and has only one X to give, the daughter could not have gotten the recessive allele from him.

​Color blindness is an X-linked recessive gene. Two normal-vision parents produce a color-blind child. (a) Is this child male or female? (b) What are the genotypes of the parents? (c) What are the chances that their next child will be a color-blind daughter?

a) male b) Cc' CY c) cannot produce color blind daughter

which of the following is the genetic condition observed in the women on the left in the above figure

achondroplasia

Various forms that a single gene can take at a given locus are called

alleles

Mendel's dihybrid crosses, but not his monohybrid crosses, show that

alleles for different traits are inherited independently

environmental effects can result in

altered phenotypes

if a daughter expresses an X-linked recessive trait, she inherited the trait from ____.

both parents

In _______, a pair of nonidentical alleles affecting the phenotypes of a given trait are both expressed at the same time in heterozygotes

codominance

height, weight, and eye color are examples of phenotypes that illustrate

continuous variation

the accompanying figure represents which chromosomal change

deletion

In which of the following does the environment play a causal role?

depression and schizophrenia

according to Mendel, if a male that is homozygous for the dominant form (PP) of a trait is crossed with a female that is homozygous for the recessive (pp) form of a trait, all offspring will show the _________ form of the trait.

dominant

(#2)The F2 phenotypic ratio of 9:3:4, as shown above, is a result of a cross involving

epistasis, in which one gene modifies the expression of the other gene

genes at one locus that affect the expression of genes at a different locus are said to be

epistatic

polyploidy can be described as ____.

fatal in humans but common in flowering plants

in the classic argument of 'nature vs. nurture' , nature would most correspond with

genes

the most accurate description of an organism with genotype AaBb is

heterozygous

who is a carrier of an X-linked trait?

heterozygous female

(#46)The accompanying illustration shows the F 2 phenotypes from a monohybrid cross in snapdragons. What type of inheritance produces such an outcome?

incomplete dominance

pleiotropic genes _____.

influence more than one aspect of phenotype

a chromosome's gene sequence that was ABCDEFG before damage and ABFEDCG after is an example of

inversion

the accompanying figure represents which chromosomal change?

inversion

achondroplasia _______.

is characterized by abnormally short arms and legs

which combination makes most sense from an evolutionary perspective

light skin and little sun, or dark skin and lots of sun

where is the CFTR gene expressed at the highest levels?

lungs

Males tend to be affected in greater numbers by X-linked recessive genetic disorders than are females because

males have only one X chromosome

a human X-linked disorder is

more frequently expressed in males

how many genes are involved in determining skin color

more than 100

the ABO blood types are an example of ____.

multiple alleles and codominance

changes in chromosome number are usually the result of

nondisjunction

question 60

on paper

a gene that produces multiple effects is called a(n)

pleiotropic gene

(#13) which offspring in the illustration above are homozygous recessive for both traits

pptt

the CFTR protein product is responsible for

pumping chloride ions out of the cell

In a certain plant, when individuals with blue flowers are crossed with individuals with blue flowers, only blue flowers are produced. Plants with red flowers crossed with plants with red flowers sometimes produce only red flowers, although other times they produce either red or blue flowers. When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced. Which gene is dominant?​

red

what can be said about sex- determination in humans

sex depends upon which type of sperm fertilizes the egg

Which most completely describes the circumstances under which yarrow will alter its phenotype?

temperature, soils conditions and water conditions

for Mendel's explanation of inheritance to be correct, ____.

the combination of gametes at fertilization must be due to chance

Amniocentesis involves sampling

the fetal cells floating in the amniotic fluid

the role of environmental factors on gene expression is illustrated by ____.

the varying plant height of genetically identical yarrow plants when grown at different elevations

a transfer of genes between non-homologous chromosomes is know as

translocation

an individual with a genetic makeup of aa BB is called

true breeding

PKU detection includes

urine analysis and blood tests at birth

​Crosses between a yellow rat with a yellow rat always produce yellow offspring. Crosses between a white rat with a white rat always produce white offspring. The alleles affect the same aspect of coat color. The cross of a white rat with a yellow rat produces a cream rat. If you cross two cream rats, what will be the ratios of phenotypes of the offspring?

yellow 1 cream 2 white 2