Practice final

Question 1

In eukaryotic cells, some genes are expressed only in particular cell types because different cell types contain:

Answer 1

different regulatory transcription factors

Question 2

What is an example of a eukaryotic transcription factor?

Answer 2

A Homebox (hox) protein

Question 3

A mediator protein regulates eukaryotic gene expression by:

Answer 3

interacting with regulatory transcription factors bound to enhancers

Question 4

Muscles cells and neurons (nerve cells) differ in the following ways:

Answer 4

• they contain diff RNA sequences
• they contain diff proteins
• they develop from diff germ layers

Question 5

Which protein is likely to have an N-terminal signal sequence?

Answer 5

epidermal growth factor

Question 6

if a human is heterozygous for the gene that encodes the protein elastase, this means that two different alleles of the elastase gene are found on:

Answer 6

the two members of a homologous chromosome pair

Question 7

Most somatic cells spend most of the cell cycle in:

Answer 7

interphase

Question 8

If a cell’s DNA is not fully replicated during S phase, the cell cycle will stop at:

Answer 8

the G2 checkpoint

Question 9

When is primase, the enzyme that makes the RNA primers used in DNA replication, most active during the cell cycle?

Answer 9

S phase, duh, hint = DNA replication

Question 10

At which of these stages of the cell cycle do cells have the largest number of chromosomes?

Answer 10

They have the same number of chromosomes in all of these stages (G1 phase, S phase, and G2 phase)

Question 11

What is the shortest phase of the cell cycle in a normal mitotic cell?

Answer 11

M phase

Question 12

What is the shortest phase of the cell cycle in an embryo undergoing rapid cleavage?

Answer 12

G1, G2; or there is no G1 or G2 phase

Question 13

What effect would this mutation have on the fertilization process:

• a mutation prevents the acrosome of a man’s sperm from undergoing exocytosis
• a mutation inactivates the proteins stored in the acrosome of a man’s sperm
• a mutation in a gene that causes the zona pellucida proteins to be unable to be modified or digested by proteases

Answer 13

• the sperm would not fertilize the egg because it would be unable to penetrate the zona pellucida that surround the egg
• the sperm would not fertilize the egg
• sperm would be unable to enter the zona pellucida because that requires digestion by acrosomal proteases, thus the egg would not be fertilized

Question 14

If you inherit a defective allele on chromosome 5 from your father, the allele will be present:

Answer 14

• in all of your somatic cells

* in half of your germ cells (gametes)

Question 15

The following terms describe key components of early development: (listed in order of appearance during development)

Answer 15

• mesoderm, notochord, neural tube, somite

Question 16

Which key components of development directly induces the formation of another?

Answer 16

• notochord induces neural tube

* neural tube induces somites

Question 17

The metaphase checkpoint (M checkpoint) stops cells from continuing the cell cycle if:

Answer 17

• chromosomes are not properly lined up on the spindle apparatus
• chromosomes have not properly segregated and MFP is absent

Question 18

At mitotic metaphase:

Answer 18

sister chromatids attach to kinetochore microtubules (spindles) from opposite poles

Question 19

Tho following statement is true about mitosis:

Answer 19

the two daughter cells are genetically identical to each other and to the mother cell

Question 20

At metaphase of the first meiotic division (meiosis I):

Answer 20

homologous chromosomes attach to opposite poles of the spindle

Question 21

Nondisjunction can result in:

Answer 21

Gametes with an extra chromosome

Question 22

The following is true concerning normal meiosis:

Answer 22

If a diploid cell starts with 2 homologous pairs of chromosomes, after meiosis II each cell will have 2 chromosomes

Question 23

A human cell that contains 23 chromosomes, each consisting of a single chromatid, has just completed:

Answer 23

meiosis II

Question 24

During the rapid cleavage stage of embryonic development:

Answer 24

the fertilized egg divides without growing, forming many cells

Question 25

Asymmetric cell division results in the production of daughter cells that:

Answer 25

contain different proteins of RNAs

Question 26

During embryonic development, neurulation results in the formation of:

Answer 26

the precursors to the brain

Question 27

In rare cases, babies are born with esophageal stenosis, a defect in the esophagus, the tube that connects the mouth to the stomach. This is most likely the result of a defect in development of the:

Answer 27

endoderm

Question 28

Human embryonic stem cells (ESCs) are derived from:

Answer 28

cells of the inner cell mass

Question 29

This class of genes is primarily responsible for encoding proteins that prevent cells from dividing if their DNA is damaged:

Answer 29

tumor suppressor genes

Question 30

What kinds of mutations would you expect to find in cancerous cells?

Answer 30

* tumor suppressor genes with mutations that inactivate the proteins they encode * proto-oncogenes with mutations that hyperactivate the proteins they encode

Question 31

How many different spliced RNAs can be produced from the primar transcript if exon 1 is always present and exons 2, 3, and 4 can each be present or absent?

Answer 31

exon 1 = 1 exon 2, 3, 4 = 2 possibilities independently of each other 2^3 = 8 posibilities

Question 32

to make a spliced RNA a mature mRNA (in a drawing)

Answer 32

add the 5' - 5'cap - poly(A)tail - 3'

Question 33

3 chromosomes is called

Answer 33

triploid