Genetics and Inheritance

Question 1

sum total of all of its DNA, even though not all of that DNA codes for proteins

Answer 1

genome

Question 2

DNA sequences that code for one or more specific proteins are called

Answer 2

genes

Question 3

the study of DNA and genes and their transmission from one generation to the next.

Answer 3

genetics

Question 4

what happens just before egg and sperm are formed so that the genes we inherit
are also different from our siblings?

Answer 4

the genes reshuffle

Question 5

variations on genes are essential for

Answer 5

evolution

Question 6

are identifiable in cells only just before cell division.

Answer 6

chromosomes

Question 7

before cell division, each chromosome can be identified by its

Answer 7

• character size
• centromere location
• distinct banding pattern

Question 8

A composite display of all the chromosomes of an organism

Answer 8

karyotype

Question 9

1-22nd chromosome

Answer 9

autosome and homologous chromosomes

Question 10

23rd chromosome

Answer 10

sex chromosome

Question 11

The sex chromosomes look different from each other and function differently because

Answer 11

they carry different genes

Question 12

Humans inherit how many of each pair of autosomes and how many sex chromosomes from each parent, giving us two copies of each gene.

Answer 12

1; 1

Question 13

may exist between any pair of autosomes.

Answer 13

small differences in DNA sequence

Question 14

Sequence differences that occur within genes thus, producing alternative versions of genes

Answer 14

Alleles

Question 15

If an individual possesses two identical alleles of a particular gene, the person is said to be ______ for that gene

Answer 15

homozygous

Question 16

A person who has two different alleles of a gene is

Answer 16

heterozygous

Question 17

an individual can only inherit how many alleles even if there are more than two alleles of a particular gene in the human population?

Answer 17

2

Question 18

Where did these different alleles come from?

Answer 18

millions of years of mutations of cells destined to be sperm or egg. and because they did not cause the cell to be nonviable, they continued.

Question 19

all the various genes and their alleles in the human population are known as the

Answer 19

human gene pool

Question 20

Your complete set of alleles

Answer 20

genotype

Question 21

the observable physical and functional traits that characterize you.

Answer 21

phenotype

Question 22

Your phenotype is determined not only by the alleles you inherit from your parents (your genotype) but also by

Answer 22

environmental factors and lifestyle

Question 23

When gametes (sperm and eggs) are formed in the parents, each gamete receives only ___ of the parents’ two alleles.

Answer 23

1

Question 24

described many of the fundamental principles of inheritance through a number of experiments involving controlled breeding of garden peas.

Answer 24

Gregor Mendel

Question 25

Most do not confer a distinct advantage or disadvantage to the homozygous recessive person.

Answer 25

recessive alleles

Question 26

These alleles no longer code for a specific essential protein because their nucleotide sequence has been altered slightly from the dominant form.

Answer 26

Alleles that result in the loss of functionality of proteuins

Question 27

In principle, the frequency of truly harmful recessive alleles in a population is kept in check by the

Answer 27

occasional premature death of homozygous recessives

Question 28

Inheritance of two copies of a harmful recessive allele may result in

Answer 28

miscarriage of a fetus

Question 29

refers only to how an allele behaves in combination with a recessive allele in a heterozygote.

Answer 29

dominant allele

Question 30

states that the alleles of different genes are distributed to egg and sperm cells independently of each other during meiosis

Answer 30

law of independent assortment

Question 31

the heterozygous genotype results in a phenotype | that is intermediate between the two homozygous phenotypes.

Answer 31

incomplete dominance

Question 32

both gene products are equally expressed

Answer 32

codominance

Question 33

Inheritance of phenotypic traits that depend on many genes

Answer 33

polygenic inheritance

Question 34

distributed to egg and sperm cells independently of each other during meiosis.

Answer 34

alleles of different genes

Question 35

Many alleles for different traits are often inherited together because

Answer 35

they are physically joined on the same chromosome.

Question 36

the closer they are located to each other on the chromosome the more likely they are to be inherited together.

Answer 36

linked alleles

Question 37

How often two linked alleles are inherited together is | clue: the more crossing-over occurs, the less likely the linked alleles will be inherited together

Answer 37

directly proportional to how close together they are and inversely proportional to how often crossing-over occurs

Question 38

technique on mapping the positions of genes by studying how often particular linked alleles are inherited together,

Answer 38

linkage mapping

Question 39

three major sources of genetic variability as a result of sexual reproduction:

Answer 39

● Independent assortment of alleles located on different chromosomes ● Partial shuffling of linked alleles as a result of crossing- over between autosomes ● Random fertilization of an egg by a sperm

Question 40

Why is the sperm of the father the determinant of the sex of the offspring?

Answer 40

Females have two X chromosomes and will donate one of them to the offspring, whereas males have an X and a Y chromosome, only one of which is donated to the offspring. If the male donates a Y chromosome, the fertilized egg has an X and a Y chromosome and will develop into a male.

Question 41

more likely to display any recessive trait found on the X chromosome, not just those that cause disease.

Answer 41

males

Question 42

In sexually reproducing animals in which the Y chromosome determines maleness, who have a homologous pair of X chromosomes?

Answer 42

females

Question 43

refers to inheritance patterns that depend on genes located on the sex chromosomes.

Answer 43

sex-linked inheritance

Question 44

Inheritance if the gene is located only on the X chromosome

Answer 44

x-linked inheritance

Question 45

inheritance if the gene is located only on the Y chromosome

Answer 45

y-linked inheritance

Question 46

apparently influence differentiation of the male sex organs, production of sperm, and the development of secondary sex characteristics, but not much else.

Answer 46

y-chromosome genes

Question 47

Hemophiliacs lack a blood-clotting factor that is encoded by

Answer 47

an x-linked gene with 2 alleles

Question 48

Testosterone strongly stimulating the expression of | the baldness allele, in effect converting it from a recessive to a dominant allele in males is an example of?

Answer 48

sex-influenced phenotype

Question 49

one not inherited with the sex chromosomes per se but influenced by the actions of the genes on the sex chromosomes.

Answer 49

sex-influenced phenotype

Question 50

People express inherited genetic disorders caused by defective recessive alleles only if they

Answer 50

get 2 of the recessive alleles

Question 51

human inherited disease in which homozygous recessive individuals are unable to make an enzyme that is needed for the normal metabolism of phenylalanine, an amino acid.

Answer 51

Phenylketonuria

Question 52

PKU is caused by mutation of the gene

Answer 52

Chromosome 1

Question 53

Chromosome 1 is responsible for

Answer 53

producing the enzyme phenylalanine hydroxylase.

Question 54

Treatment of PKU requires limiting

Answer 54

dietary intake of Phenylalanine

Question 55

enzyme deficiency disease, this one caused by a recessive gene located on chromosome 15

Answer 55

tay-sachs

Question 56

Individuals homozygous for the recessive allele in Chromosome 15 are unable to make an enzyme that is responsible for the metabolism of a particular type of lipid,

Answer 56

sphingolipid

Question 57

Without this enzyme, the _______ accumulates in brain cells, causing cerebral degeneration

Answer 57

sphingolipid

Question 58

marked by progressive nerve degeneration leading to physical and mental disability and death.

Answer 58

Huntington's disease

Question 59

HD is called a

Answer 59

Dominant-Lethal Allele

Question 60

are by their nature uncommon because they tend to eliminate themselves from the population, especially if they cause disease before the affected individual’s reproductive years.

Answer 60

dominant-lethal alleles