EXAM 3

Question 1

Cytokinesis in plant cells utilizes a _________ while animal cells utilize a ________.

Answer 1

cell plate, cleavage furrow

Question 2

Karyokinesis is _________ division while cytokinesis is ___________ division

Answer 2

nuclear, cytoplasmic

Question 3

prokaryotic cell division occurs via ___________

Answer 3

binary fission

Question 4

the correct order of the cell cycle is which of the following

Answer 4

G1, S, G2, prophase, metaphase, anaphase, telophase, cytokinesis

Question 5

the role of meiosis is ______

Answer 5

production of gametes

Question 6

the role of mitosis is __________

Answer 6

all of the answers are correct; 1)asexual reproduction, 2)growth, 3)development

Question 7

the failure of chromosomal material to separate properly during meiosis is called ___________

Answer 7

non-disjunction

Question 8

what is it called when eukaryotic cells stop dividing upon touching other eukaryotic cells?

Answer 8

density-dependent inhibition

Question 9

when a cell “realizes” that it is dividing out of control it can make “suicide proteins” to destroy itself and prevent tumors from appearing. this process is called __________

Answer 9

apoptosis

Question 10

when a tumor-cells grow through the basal lamina and enters the bloodstream it is said to have _____________

Answer 10

metastisized

Question 11

Mr. and Mrs. Smith have three sons in elementary school. Two of their children are progressing normally, but their last son, Charles, has been much slower than his siblings at developing speech and language skills. His parents are concerned that he has a learning disability and decide to investigate further. Since some learning disabilities can be genetically based, their pediatrician recommends a chromosomal analysis.

The results show that Charles has a trisomy of the sex chromosomes, diagnosed as XYY, which is caused by nondisjunction in the formation of the father’s sperm. The nondisjunction resulted in an extra copy of the Y chromosome. The extra copy was passed on to Charles during fertilization. Most often, this chromosomal change causes no unusual physical features or medical problems, but those with trisomy of the sex chromosomes do have a higher than normal risk of delays in learning development.

During which stage of meiosis could this nondisjunction have occurred?

Answer 11

anaphase II

Question 12

if a chromosome fragment breaks off and then reattaches to the original chromosome, but in the reverse direction, the resulting chromosomal abnormality is called a(n)

Answer 12

inversion

Question 13

karotyping

Answer 13

can reveal alterations in chromosome number

Question 14

all the offspring of a cross between a black-eyed fly and an orange-eyed fly have black eyes. this means that the allele for black eyes is _______ the allele for orange eyes.

Answer 14

dominant to

Question 15

asexual reproduction requires _____________ individuals

Answer 15

1

Question 16

assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couples first-born child is female and second-born child is male?

Answer 16

25%

Question 17

How many sex chromosomes are in a human gametes

Answer 17

one

Question 18

Mendel conducted his more memorable experiments on

Answer 18

peas

Question 19

two genes found near each other on the same chromosome are called what?

Answer 19

linked genes

Question 20

what is a testcross

Answer 20

a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of intrest

Question 21

what is the normal complement of sex chromosomes in a male mammal?

Answer 21

one X chromosome and one Y chromosome

Question 22

when more than one allele is expressed in a heterozygous individual, this is called ______

Answer 22

codominance

Question 23

when the expression of one gene alters the expression of another gene, this is called _____________

Answer 23

epistasis

Question 24

After reading the paragraph, answer the question(s) that follow.

A woman has been trying to conceive for several years, unsuccessfully. At a fertility clinic, they discover that she has blocked fallopian tubes. Using modern technologies, some of her eggs are removed, fertilized with her husband’s sperm, and implanted into her uterus. The procedure is successful, but the couple discovers that their new son is color-blind and has blood type O. The woman claims that the child can’t be theirs since she has blood type A and her husband has type B. Also, neither parent is color-blind, although one grandparent (the woman’s father) is also color-blind.

As a genetic counselor, you would explain to the parents that

Answer 24

each parent could have contributed one recessive allele, resulting in type O blood

Question 25

After reading the paragraph, answer the question(s) that follow. A woman has been trying to conceive for several years, unsuccessfully. At a fertility clinic, they discover that she has blocked fallopian tubes. Using modern technologies, some of her eggs are removed, fertilized with her husband's sperm, and implanted into her uterus. The procedure is successful, but the couple discovers that their new son is color-blind and has blood type O. The woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is color-blind, although one grandparent (the woman's father) is also color-blind. In regard to the baby's color blindness, a sex-linked recessive trait, you explain that

Answer 25

since color blindness is sex-linker, a son can inherit color blindness if his mother has the recessive color blindness allele

Question 26

the individual features of all organisms are the result of

Answer 26

genetics and the environment

Question 27

During the S-phase of the cell cycle, DNA _________ occurs

Answer 27

replication

Question 28

the directions for each amino acid in a polypeptide are indicated by a condon that consists of ____________ nucleotides in an RNA molecule

Answer 28

3

Question 29

the monomers of DNA and RNA are

Answer 29

nucleotides

Question 30

the synthesis of polypeptide chains from an RNA message is called

Answer 30

translation

Question 31

the transfer of genetic information from DNA to RNA is called

Answer 31

transcription

Question 32

which of the following enzymes synthesizes a new DNA strand

Answer 32

DNA polymerase

Question 33

which of the following enzymes unwinds a DNA double helix

Answer 33

helicase

Question 34

which of the following enzymes "glue" strands of DNA together

Answer 34

ligase

Question 35

which of the following people conducted experiments that demonstrated that DNA is a helix

Answer 35

Watson, Crick, and Franklin

Question 36

which one of the following sequences best describes the flow of information when a gene directs the synthesis of a cellular component

Answer 36

DNA > RNA > Protein

Question 37

what nucleotide sequence would be found on the partner DNA strand of the strand shown(ACTGT)

Answer 37

TGACA

Question 38

After reading the paragraph, answer the question(s) that follow. Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect against HIV infection. The mutation probably originated in Europe among survivors of the bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes and, therefore, from entering and infecting body cells. Although the HIV virus is very different from the bacteria that causes the plague, both diseases affect the exact same cells and use the same method of infection. The presence of the mutated gene in descendants of plague survivors helps prevent them from contracting AIDS. Pharmaceutical companies are using this information as the basis for a new approach to AIDS prevention. This would be very important in areas of the world where the mutation is scarce or absent, such as Africa. Which of the following shows the steps of a viral infection in the proper order?

Answer 38

virus locates host cell > penetrates cell membrane > enters nucleus > alters host cell DNA > host cell produces copies of virus

Question 39

In the 1920s, Frederick Griffith conducted an experiment in which he mixed the dead cells of a bacterial strain that can cause pneumonia with live cells of a bacterial strain that cannot. When he cultured the live cells, some of the daughter colonies proved able to cause pneumonia. Which of the following processes of bacterial DNA transfer does this experiment demonstrate?

Answer 39

transformation

Question 40

Binary fission

Answer 40

1) duplication of the chromosomes, 2) continued elongation *pinches in 3) division into two daughter cells

Question 41

nuclear division

Answer 41

(mitosis & meiosis), called karyokinesis, division of chromosomes

Question 42

cytokinesis

Answer 42

division of organelles and cytoplasm, comes after nuclear division

Question 43

nucleosome

Answer 43

histone proteins, 2 wraps of DNA around 8 unit histone

Question 44

euchromatin

Answer 44

interphase

Question 45

heterchromation

Answer 45

when cell division is occurring

Question 46

non-dividing stages

Answer 46

G1 (cell increases size and number of organelles), S (chromosome replication), G2 (cell synthesizes molecules needed for division

Question 47

dividing stages

Answer 47

mitosis, cytokinesis

Question 48

nerve cells

Answer 48

never divide again

Question 49

liver cells

Answer 49

can re-enter cell cycle

Question 50

skin cells

Answer 50

divide constantly

Question 51

anchorage

Answer 51

single layer of cells, removal of cells, restoration of single layer by cell division

Question 52

tumors

Answer 52

lack of contact inhibition

Question 53

meiosis 1

Answer 53

function: separate homologous pairs, go from diploid to haploid

Question 54

meiosis 2

Answer 54

separate sister chromatids, go from double to single stranded

Question 55

abnormal # of sex chromosomes or autosomes

Answer 55

ex. extra chromosome, trisomy -21, down syndrome

Question 56

deletion

Answer 56

loss of a fragement

Question 57

duplication

Answer 57

addition of an identical fragment

Question 58

translocation

Answer 58

attachment of a non-homologous chromosome fragment

Question 59

animal cloning involves

Answer 59

nuclear transfer

Question 60

gel electrophoresis sorts DNA molecules on the basis of their

Answer 60

size

Question 61

PCR is a technique used to

Answer 61

make billions of copies of a single gene in vitro

Question 62

RFLP is a technique used to

Answer 62

create DNA fingerprints based on nucleotide sequence

Question 63

Restriction enzymes

Answer 63

cut DNA at specific sequences

Question 64

the production of multiple identical copies of genes defines

Answer 64

gene cloning

Question 65

which of the following is used to protect against accidents involving genetically engineered organisms

Answer 65

genetic sterilization of the recombinant organsim

Question 66

which statement is correct? Embryonic stem cells can be used to create

Answer 66

any cell type

Question 67

approximately what percentage of human DNA is noncoding

Answer 67

99%

Question 68

Genomic libraries can be constructed using either bacterial plasmids or what other vector?

Answer 68

bacteriophages

Question 69

the enzyme that converts information stored in their RNA to information stored in DNA is

Answer 69

reverse transcriptase

Question 70

what is the preferred name of the technique used to determine if DNA comes from a particular individual?

Answer 70

Dna profiling

Question 71

if you commit a crime, you need to make sure that you do note leave even the smallest speck of blood, hair, or other organic matter from tour body. if you do, the DNA in this material can be amplified by ____________, subjected to genetic analysis, and used to identify you as the perpetrator of the crime

Answer 71

PCR

Question 72

monohybrid cross

Answer 72

traits differ at one characteristic

Question 73

p gen

Answer 73

true breeding parents

Question 74

gene

Answer 74

DNA at a specific location on chromosomes that codes for a polypeptide that determines particular characteristics

Question 75

locus

Answer 75

any specific location on a chromosome whether it codes for characteristics or not

Question 76

allele

Answer 76

different variation of a given gene

Question 77

recessive allele

Answer 77

only expressed when its homozygous

Question 78

phenotype

Answer 78

outward physical appearance

Question 79

genotype

Answer 79

internal genetic makeup

Question 80

dihybrid cross

Answer 80

traits differ at two characteristics

Question 81

incomplete dominance

Answer 81

allele neither dominant nor recessive

Question 82

pleiotropy

Answer 82

one gene influences many characteristics ex. sickle cell anemia

Question 83

where is the genetic material

Answer 83

on the chromosomes, inside nucleus

Question 84

transduction

Answer 84

transfer of bacterial genes by a phage (virus)

Question 85

reterovirus

Answer 85

ex. HIV

Question 86

DNA | what makes up DNA?

Answer 86

sugar(deoxyribose), phosphate, nitrogenous base

Question 87

DNA nitrogenous bases

Answer 87

adenine, thymine, guanine, cytosine

Question 88

A & T

Answer 88

two bonds

Question 89

G & C

Answer 89

three bonds

Question 90

pruines

Answer 90

A and G

Question 91

pyrimidines

Answer 91

T and C

Question 92

RNA nitrogenous bases

Answer 92

Adenine, Guanine, Cytosine, Uracil

Question 93

3 major types of RNA

Answer 93

mRNA, rRNA, tRNA

Question 94

animal cloning

Answer 94

reproductive and therapeutic

Question 95

which of the following statements regarding the function of mitosis is FALSE

Answer 95

mitosis allows organisms to generate genetic diversity

Question 96

anaphase

Answer 96

chromosomes move toward opposite poles

Question 97

prometaphase

Answer 97

nuclear envelope fragments

Question 98

prophase

Answer 98

chromosomes condense and become visible

Question 99

metaphase

Answer 99

chromosomes line up on the equator of the cell

Question 99

telophase

Answer 99

daughter nuclei form

Question 100

diploid

Answer 100

two copies of the chromosomes

Question 100

at the end of prophase of mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called

Answer 100

sister chromatids

Question 100

haploid

Answer 100

one copy of the chromosomes

Question 100

two differences between mitosis and meiosis

Answer 100

1)meiosis makes 4 haploid cells and mitosis makes only 2 diploid cells 2)meiosis makes unique cells, mitosis identical cells

Question 101

what is crossing over? during which meiotic phase does crossing over take place?

Answer 101

exchange of genetic material between homologous pairs of chromosomes, happens during prophase 1 of meiosis

Question 102

during what stage of meiosis do sister chromatids separate from each other?

Answer 102

anaphase 2

Question 103

two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are

Answer 103

homologous chromosomes

Question 104

Mendel's law of independent assortment states that

Answer 104

each pair of alleles segregates independently of the other pairs of alleles during gamete formation

Question 105

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes?

Answer 105

Dd and Dd

Question 106

a person with AB blood illustrates the principle of

Answer 106

codominance

Question 107

which of the following is an example of incomplete dominance in humans?

Answer 107

hypercholesterolemia

Question 108

A colorblind woman marries a man who is not colorblind. All of their sons, but none of their daughters, are colorblind. Which of the following statements correctly explains these results?

Answer 108

the gene for color vision is found on the x chromosome

Question 109

the 4 o'clock flower is an example of incomplete dominance: R=red, r=white, and Rr=pink. if two hybrids are crossed, what are the chances that an offspring will have pink flowers?

Answer 109

50%

Question 110

traits that are controlled by several sets or pairs of alleles, such as skin color and height in humans, are ht result of what form of inheritance

Answer 110

polygenic inheritance

Question 111

difference in the nucleotide structure of DNA and RNA

Answer 111

DNA: deoxyribose, double stranded, A,C,G,T, in nucleus. RNA:ribose, singel stranded. A,C,G,U, in nucleus and cytoplasm

Question 112

which of the following statements about DNA replication is INCORRECT?

Answer 112

replication occurs as each base is paired with another exactly like it

Question 113

when one DNA molecule is copied to make two DNA molecule, the new DNA contains:

Answer 113

50% of the parent DNA

Question 114

why does a new DNA strand grow in only the 5' to 3' direction?

Answer 114

DNA polymerase only binds the 3' end and then moves 3' to 5' on the template strand

Question 115

In DNA replication, what is the structural difference between the leading and the lagging strands?

Answer 115

leading strand: continuous (DNA polymerase move towards replication fork). lagging strand: made in fragments called Okazaki fragments (DNA polymerase moves away from the replication forks).

Question 116

during the process of transcription, the information in

Answer 116

DNA is converted into RNA information

Question 117

which of the following options most accurately lists the sequence of events during elongation of an amino acid sequence in translation?

Answer 117

condon recognition > peptide bond formation > mRNA moves forward by one condon

Question 118

a particular triplet of bases in the template strand of DNA is AAA. the anticodon on the tRNA that binds to the RNA codon that was transcribed from the template DNA is:

Answer 118

AAA

Question 119

gene mutations are

Answer 119

alterations in the normal sequences of bases within a gene

Question 120

the term "gene expression" refers to the

Answer 120

process by which genetic information flows from genes to proteins

Question 121

a gene operon consists of

Answer 121

transcribed genes, an operator, and a promoter

Question 122

proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called

Answer 122

activators

Question 123

the lac operon of E. coli is _________ when the repressor is bound to lactose.

Answer 123

active

Question 124

which of the following statements regarding DNA packing is false?

Answer 124

DNA packing tends to promote gene expression

Question 125

which of the following permits a single gene to code for more than one polypeptide

Answer 125

alternative RNA splicing

Question 126

RNA interference (RNAi) can be used by

Answer 126

cells to prevent infections from double-stranded RNA viruses

Question 127

viral DNA incorporated into host cell DNA is known as a

Answer 127

prophage

Question 128

conjugation

Answer 128

is the direct transfer of DNA from one bacterium to another

Question 129

when DNA from two sources is combined into one single piece of DNA, it is known as

Answer 129

recombinant DNA

Question 130

when plasmids are used to produce a desired protein

Answer 130

the desired gene is inserted into the plasmid, and the plasmid is returned to the bacterium by transformation

Question 131

"sticky ends" are

Answer 131

DNA fragments with single-stranded ends

Question 132

after DNA fragments with matching sticky ends are temporarily joined by complementary base pairing, the union can be made permanent by the "pasting" enzyme

Answer 132

ligase

Question 133

which of the following is the best definition of a genomic library

Answer 133

a collection of cloned DNA fragments that includes an organism's entire genome

Question 134

the enzyme that converts information stored in RNA to information stored in DNA is

Answer 134

reverse transcriptase

Question 135

a nucleic acid probe is

Answer 135

a piece of radioactively labeled DNA that is used to locate a specific gene