module 2 exam

surface-to-volume ratio is an important characteristic for cell function; some cells increase their ratio by

developing finger-like prongs

a translocation may lead to cancer if it

disrupts control of expression of genes that regulate the cell cycle.

if the maternal X chromosome is inactive and becomes the Barr body in one cell, then the maternal X chromosome becomes the Barr body in every cell of that woman's body.

false

the genetic code in bacteria is different than the genetic code in animals and plants.

false

the repressor protein used by Escherichia coli to control the lac operon is coded for by a gen e located within the operon.

false

the unpacking of heterochromatin into euchromatin does not immediately result in DNA transcription because

histones still block the binding of RNA polymerase to the promoter

the x-ray diffraction pattern of DNA discovered by Rosalind Franklin showed that DNA

is both helical and has a repeating pattern

which of the following statements describes the function of chloroplast

it converts light energy into chemical energy

the cell walls of bacterial cells and plant cells function in

maintaining cell shape

when a portion of a chromosome breaks off and attaches to a different chromosome, this is called a

translocation

histone displacement is necessary for transcription to occur in euchromatin

true

proteins are active immediately after translation occurs

true

stem cells that contain telomerase can be found in adults.

true

the two DNA strands must be separated before DNA replication or transcription can occur

true

translocations can lead to cancer if they disrupt the genes that regulate the cell cycle.

true

if an organism's DNA contains 30% adenine nucleotides, what percentage of its DNA is composed of thymine nucleotides?

30%

a call is inhibited during the S phase of its cycle. it will not reproduce due to the lack of

DNA synthesis

DNA replication makes a(n) ________ copy of the DNA strand, while transcription makes a(n) ________ copy of the DNA strand.

DNA; mRNA

cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. which of the following statements explains why this occurs?

cell division can be inhibited by the proximity of other cells of the same type, a process called contact inhibition

which of the following human cells would contain cilia

cell from the trachea (windpipe)

plant cells have plasmodesmata

connect the cytoplasm of one cell with that of another.

there is an antibiotic called streptomycin that inhibits the function of bacterial ribosomes. Consequently, as the bacterial cells die, the person taking the antibiotics gets better. In other words, the antibiotic destroys bacteria by

not allowing them to produce proteins

chromatin wrapped around histones form a bead-like structure known as a

nucleosome

the nucleus has a double membrane that encloses the DNA. Inside the nucleus, the DNA acts as the template to produce mRNA and ribosomes.To exit the nucleus, these molecules must

pass through pores that span both membranes

what must materials pass through to enter or leave a cell?

plasma membrane

which feature is found in all cells?

plasma membrane composed of phospholipids

both plants & animals need mitochondria to

produce ATP

unicellular organisms undergo mitotic division to

produce new organisms

which items in the following pairs are correctly matched?

s phase - DNA replication

if a cell stops at the G1 checkpoint, this is most likely due to what problem?

there is DNA damage