Simbio DNA Explored

Question 1

Amino acid

Answer 1

• small molecule that can be joined together with other amino acids (by ribosomes) to form a polypeptide
• proteins are made of one or more polypeptides

Question 2

Operon

Answer 2

• A region of DNA that contains several adjacent genes that are transcribed from a single promoter
• Genes in the operon are usually functionally related to each other

Question 3

Promoter

Answer 3

• Short segment of DNA that serves as a binding site for RNA polymerase to initiate transcription of a gene or operon

Question 4

Regulatory Sequence

Answer 4

• short sequence of DNA that’s involved in controlling gene expression
• Promoters, operators and activator sites are all regulatory sequences

Question 5

Ribosome

Answer 5

• assembles amino acids into proteins by using mRNA information
• performs translation

Question 6

Can translation happen before transcription? Why or why not?

a) Yes, because DNA is present
b) Yes, because proteins are produced
c) No, because the messenger molecule is absent

Answer 6

c) No, because the messenger molecule is absent

Question 7

How does a bacterial cell express genes?

a) It converts DNA molecules into protein molecules by assembling proteins from pieces of DNA
b) It uses the information in DNA to make an intermediate molecule, which is then used to build a protein
c) It uses the information in DNA to directly construct a protein

Answer 7

b) It uses the information in DNA to make an intermediate molecule, which is then used to build a protein

Question 8

Which of the following are secreted by the cell to break down intestinal tissue?

a) DNA
b) Genes
c) Proteins

Answer 8

c) Proteins

Question 9

What is attached to the 3’ carbon deoxyribose?

a) An OH group
b) A phosphate group
c) a base

Answer 9

a) An OH group

Question 10

Which carbon in deoxyribose is the phosphate group attached to?

Answer 10

5’ carbon

Question 11

What does it mean to say that polymerization proceeds 5’ to 3’?

Answer 11

DNA polymerase always adds nucleotides onto the 3’ end of a DNA strand

Question 12

Phosphodiester bond

Answer 12

• connects successive nucleotides in a strand of nucleic acid
• involves covalent bonding with a phosphate group that links the 3’ carbon of one nucleotide to the 5’ carbon of the next

Question 13

How many H bonds do adenine and thymine have?

Answer 13

2

Question 14

How many H bonds do cytosine and guanine have?

Answer 14

3

Question 15

Would it be harder to separate AT or GC base pairs? Why?

Answer 15

GC because they have more H bonds than AT

Question 16

Which way does helicase move along DNA?

Answer 16

Away from the origin of replication

Question 17

Which of the following is generally true about DNA within the replication bubble?

Answer 17

It’s single stranded

Question 18

What is topoisomerase?

Answer 18

• an enzyme that relaxes the over-winding of DNA that results from separating DNA strands during replication

Question 19

What happens if there is no topoisomerase?

Answer 19

• helicase won’t be able to separate the strands of DNA because there would be too much tension from over-wound helices
• topoisomerases work ahead of helicase

Question 20

Origin of replication

Answer 20

• the locations on each DNA molecule (chromosome) where DNA replications begin
• specific locations where the pre-replication complex of proteins bind to initiate DNA replication

Question 21

Single-stranded binding protein (SSBP)

Answer 21

• attaches to single-stranded DNA to prevent the DNA from reforming a double helix
• loaded onto DNA in the replication bubble after helicase will unzip the DNA strands
• removed by primase and DNA polymerases because they will reform the double helix

Question 22

Replication bubble

Answer 22

• region b/w two helicase proteins where DNA is actively being replication
• DNA is single-stranded within the bubble
• each bubble has two replication forks
• 2 leading and lagging strands in each bubble