exam 2

Question 1

T/F the codon UGA, in some cases may act as a stop codon in mRNA

Answer 1

True

Question 2

T/F anticodon CGI in tRNA may pair with GCU codon of an mRNA molecule

Answer 2

True

Question 3

T/F mRNA is translated in the 3’ to 5’ direction

Answer 3

False

Question 4

T/F Binding of RNA polymerase II to DNA requires the presence of translation factor

Answer 4

False

Question 5

T/F During translation, the mRNA codon AUG is recognized by the amino acid methionine attached to the tRNA containing UAC anticodon

Answer 5

True

Question 6

5’ capping, addition of 3’ poly A tail, and removal of introns to generate a final mRNA from the primary RNA transcript that serves as its precursor

Answer 6

modification and processing

Question 7

portion of a gene containing TATA box, CAAT box, GC box and Enhancer base sequences

Answer 7

Promoter

Question 8

it assembles at editsomes and corrects the mRNA transcript if it is different from the corresponding gene

Answer 8

guide RNA

Question 9

A portion of DNA, the first codon of which is TAC at the 3’ end, and the last codon of which could be ATC at its 5’end

Answer 9

Gene

Question 10

A core promoter, proximal control elements and a transcription unit in DNA

Answer 10

activation

Question 11

The process of copying the DNA to make two identical DNA’s

Answer 11

replication

Question 12

The transmission of genetic cod from a gene to an mRNA

Answer 12

transcription

Question 13

The process of decoding the genetic message in mRNA

Answer 13

translation

Question 14

the linear sequence of bases in the DNA molecule that determines the linear sequence in an mRNA, which determines the amino acid sequence in a protein

Answer 14

genetic code

Question 15

Binding of tRNA and some other components to the ribosomes, transpeptidation and translocation of the empty tRNA

Answer 15

elongation

Question 16

If a GAA codon from glutamine mutated to GUA, which now codes for valine, this will be considered ____ type of point mutation

Answer 16

missense

Question 17

If a UUA codon for leucine mutated to UAA, which now becomes a stop codon, this will be considered ___ type of point mutation

Answer 17

nonsense

Question 18

T/F cancer cells prevent the shortening of their chromosomal telomeres by self-destructing their telomerase enzyme, which stabilizes the telomere length

Answer 18

False

Question 19

T/F Elongation of protein synthesis occurs at the A site of the ribosome

Answer 19

True

Question 20

Decodes the message during translation

Answer 20

tRNA

Question 21

codes for protein

Answer 21

mRNA

Question 22

components of ribosome and acts as ribozyme

Answer 22

rRNA

Question 23

synthesizes leading and lagging sttrands

Answer 23

DNA polymerase III

Question 24

joins together adjacent Okazaki pieces after the removal of RNA protein

Answer 24

DNA ligase

Question 25

removes RNA primers and fills the gap

Answer 25

DNA polymerase I

Question 26

promotes separation of the 2 DNA strands by inducing negative supercoiling

Answer 26

topoisomerase (gyrase)

Question 27

What can occur in the development of cancer?

Answer 27

angiogenesis occurs, cells are immortal, and cell metastasize (no benign cell growth)

Question 28

T/F oncogenesis caused by a retrovirus is by radiation, loss of tumor-suppressing gene, or a carcinogen activates the latent provirus gene which causes the transformation of a normal cell into a cancer cell

Answer 28

True

Question 29

in regulation of protein synthesis, if the enzyme is not synthesized it is called___ whereas if the enzyme is synthesized, but its activity suppressed it is called___

Answer 29

enzyme repression, end-product inhibition

Question 30

T/F Xeroderma pigmentosum have reverse transcriptase activity

Answer 30

False (retroviruse) -are sensitive to sunlight, their skin cells are unable to repair thymine dimers, develop freckling, and may develop melanoma

Question 31

CTC codon in hemoglobin gene changed to CAC

Answer 31

sickle cell anemia

Question 32

an abnormal growth of new tissue forming a lump that stays within the original tissue

Answer 32

neoplasm

Question 33

the development of blood supply by the cancerous cells

Answer 33

angiogenesis

Question 34

Several cell cycle checkpoints regulate progression through the cell cycle. These include ____ checkpoint

Answer 34

G1, G2, S phase

Question 35

T/F formation of chiasma occurs in mitosis

Answer 35

false | -disappearance of the nuclear membrane and nucleoli, formation of spindle apparatus, and separation of sister chromatids

Question 36

the nucleus has the following functions

Answer 36

cell's command center, contains genes, and is thus involved in heredity

Question 37

Which enzyme is NOT involved in DNA repair process

Answer 37

DNA polymerase III

Question 38

Assume that you have an mRNA, which is 27-base long (including the initiator codon AUG and the sop codon UAA). During or after protein synthesis, the 5' end methionine was cleaved off. In addition, one codon was removed due to mutation, but that did not affect protein synthesis, and it went on as usual. The completed polypeptide chain would have how many amino acid in it?

Answer 38

6

Question 39

growth due to excess multiplication of cells

Answer 39

neoplasm

Question 40

noncancerous growth

Answer 40

benign tumor

Question 41

cancer arising form connective tissue

Answer 41

sarcoma

Question 42

proliferation of leukocytes

Answer 42

leukemia

Question 43

tumor of epithelial cells

Answer 43

carcinoma

Question 44

If mutation occurs in the DNA and DNA repair is unsuccessful for some reason, P53 prevent proliferation of the genetically damaged cell by triggering cell suicide, a process commonly known as

Answer 44

apoptosis

Question 45

Transcription in eukaryotic cells is directly involved with what flow of genetic information

Answer 45

DNA to RNA

Question 46

Processing the primary mRNA transcript is necessary because:

Answer 46

introns have to be cut out since they don't make genetic sense

Question 47

Which one is not part of the "promoter" in DNA

Answer 47

operator | -TATA sequence, enhancer, CAAT sequence

Question 48

as the ribosome moves along each mRNA codon, additional amino acids are transferred into place by ___-RNA_____ bonds from bw adjacent AA with the help of an enzyme provided by the

Answer 48

tRNA; Peptide; ribosome

Question 49

UV radiation to DNA causes mutation by replacing a purine by pyrimidine. This is known as..

Answer 49

Transversion

Question 50

High fat consumption is the dietary factor associated with high risk of the development of all but which type of cancer

Answer 50

colon cancer

Question 51

The genetic code is degenerate. This means that

Answer 51

a. the codons AUG, and sometimes GUG act as a start codons B. most codons differ only in their third base in the nucleotide C. The genetic code is universal D. Several codons specify the same amino acid E. The genetic cold degenerates after each replication

Question 52

An enhancer in the promoter is crucial for the following functions except:

Answer 52

enhances transcription of the gene upstream - is the "entry point" of DNA for RNA polymerase II enzyme - May alter DNA's topography - May mediate selective gene expression

Question 53

Introns contain the information for making a polypeptide

Answer 53

False

Question 54

In telophase I of meiosis, each chromosome in each cell has only one DNA

Answer 54

false

Question 55

Alfotoxin B1 is potent antioxidant which prevents the development of cancer

Answer 55

False

Question 56

Most protein synthesis occurs in the

Answer 56

cytoplasm

Question 57

The difference bw DNA and RNA are in

Answer 57

- number of strands in a molecule - base composition - sugar composition - Rate of synthesis and degradation of the average molecule

Question 58

The following are true of messenger RNA exept

Answer 58

DNA codons. GCA becomes mRNA condon CGT - When DNA unwinds in the synthesis of mRNA, only one of the two DNA chains is used to form a single mirror-image chain of mRNA - the formation of mRNA does not involve making a mirror -image of the entire DNA molecule - DNA codon CGT becomes mRNA codon GCA

Question 59

What is the name of the bond which is formed bw two amino acids during protein synthesis?

Answer 59

peptide bond

Question 60

An operon is

Answer 60

a group of structural genes

Question 61

Activation of the repressor substance will

Answer 61

A stop biological synthesis

Question 62

When E.coli is grown in a medium to which histidine is added all the enzymes required for the synthesis of histidine are simultaneously inhibited. What is the process called?

Answer 62

enzyme repression