Biology Grade 12 Review P3

Front 1

Base pairing due to hydrogen bonding is fundamental to

Back 1

The process of DNA Replication and DNA Transcription

Front 2

In eukaryotes, introns are removed before mRNA leaves the nucleus because

Back 2

they do not code for protein

Front 3

Line A shows the peptide synthesized after transcription and translation of a piece of DNA. Line B shows the peptide synthesized after a mutation in this piece of DNA. (A) proline - arginine - aspartic acid - lysine - glycine; (B) proline - glutamine - aspartic acid - lysine - glycine. The type of change in the DNA most likely to be responsible for the difference between the peptides is

Back 3

a base substitution

Front 4

Which of the following is not accurate?

Back 4

The spliceosomes are larger in eukaryotes than in prokaryotes.

Front 5

The arrangement of bases in a molecule of mRNA is best described as

Back 5

linear

Front 6

The splicing of the first-formed mRNA transcript by spliceosomes is necessary because

Back 6

introns need to be removed

Front 7

DNA acts as a template for transcription. Which of the following statements regarding the DNA of a gene being expressed is true?

Back 7

After unwinding, only one of the DNA strands acts as a template.

Front 8

A cell in cell culture is briefly immersed in radioactive uracil. After a short time, the radioactive uracil is removed and the cell culture is washed with, and immersed in, nonradioactive uracil. Where would you expect to find the main concentration of radioactive nucleic acid? (I) Immediately after immersion in the radioactive uracil solution; II. Some time after the cell was returned to nonradioactive uracil.

Back 8

I. in the nucleus; II. in the cytoplasm

Front 9

Compare the two mRNA sequences: (1) AUAUUCGGCAAUCCG, and (2) AUUCCGCAAUCCG. This change could be the result of a

Back 9

point mutation

Front 10

hich of the following correctly describes the order in which cell components become involved in protein synthesis?

Back 10

RNA polymerase, mRNA, ribosome, tRNA

Front 11

When recombinant DNA is formed, it is necessary to join the sugar-phosphate backbones of the plasmid DNA and the introduced DNA. Which of the following is used to do this?

Back 11

ligase

Front 12

When gel electrophoresis is undertaken, one well always contains DNA-marker molecules. The purpose of these markers is to

Back 12

serve as a guide to the length of the fragments in the other wells

Front 13

What kind of reaction does DNA ligase catalyze?

Back 13

condensation

Front 14

The restriction endonuclease AluI leaves blunt ends on DNA fragments after digestion. These blunt ends

Back 14

are fully base paired

Front 15

The relationship between plasmids and bacteria is said to be endosymbiotic. This is because

Back 15

the plasmid exists within the bacterium and the relationship of bacterium and plasmid is mutually beneficial

Front 16

The following are all steps in the production of a bacterium having recombinant DNA, which includes an inserted nonbacterial gene. They are in random order: (1) gel electrophoresis of plasmid DNA from bacteria in colonies showing antibiotic resistance; (2) sticky ends are allowed to pair up; (3) a restriction endonuclease is used to remove the gene to be inserted from its source and also to cut open a plasmid that includes a gene for antibiotic resistance; (4) the bacterial colonies are treated with antibiotic; (5) treatment with ligase; and (6) transformation. The correct order of these steps is:

Back 16

3,2,5,6,4,1

Front 17

The discovery of restriction endonucleases was crucial to the development of recombinant DNA technology because these enzymes

Back 17

cut DNA at specific and predictable sequences of bases

Front 18

The competency of bacterial cells to take up plasmids from the environment can be enhanced by treating them with calcium chloride. Which of the following statements is true regarding this process?

Back 18

Calcium ions neutralize charges on the phospholipids of the bacterial cell membrane and on the DNA of the plasmid.

Front 19

Gel electrophoresis separates fragments of DNA using

Back 19

a sieving medium through which DNA molecules are moved by electrical forces

Front 20

Devices that help to loosen the structure of cell walls aid in the transformation of bacterial cells. These devices are called

Back 20

electroporators

Front 21

A plasmid was treated with a methylase enzyme and then with two restriction endonucleases. If the resulting DNA fragment(s) were run on a gel using electrophoresis, how many band(s) would you expect to see?

Back 21

1

Front 22

A fragment of DNA is called recombinant if

Back 22

it contains DNA sequences from more than one source

Front 23

A DNA nucleotide contains: (1) a cyclic nitrogen-containing part; (2) a single ring containing five carbons; and (3) a part which contains four oxygen atoms surrounding a central atom. In order, 1, 2 and 3 are:

Back 23

a sugar, a base, a phosphate group

Front 24

A mutant form of E. coli has been discovered in which replication is unsuccessful because the RNA primer is not released from the template strand. Which enzyme do you think is nonfunctional?

Back 24

DNA polymerase I

Front 25

Before the mRNA transcript is ready to be translated by a ribosome into a protein, the introns are cut out and the exons are joined together by:

Back 25

spliceosomes

Front 26

Complementary base pairing is the result of

Back 26

hydrogen bonding

Front 27

During DNA replication, one of the new strands of DNA is synthesized continuously, while the other is synthesized as a number of separate fragments of DNA that are subsequently linked by DNA ligase. This is because

Back 27

DNA polymerase III only synthesizes DNA in the 5' - 3' direction

Front 28

During translation, tRNAs drop off their _______________ at the ribosome and a polypeptide chain is formed.

Back 28

amino acids

Front 29

In a eukaryotic cell, the sizes of the large and small ribosome subunits are, respectively

Back 29

60S, 40S

Front 30

Restriction endonuclease digestion of a DNA sequence yielded fragments of the following sizes: 1) 5.2 kb; 2) 0.8 kb; 3) 1.2 kb; 4) 3.8 kb; 5) 3.1 kb. After gel electrophoresis, what would be the order in which these fragments would be found?(The last fragment listed being furthest from the negative pole).

Back 30

1,4,5,3,2

Front 31

RNA polymerase participates in

Back 31

DNA transcription

Front 32

Sticky ends are short single-stranded lengths of DNA sticking out from double-stranded DNA that has been cut using certain restriction endonucleases.

Back 32

True

Front 33

The (almost) universal start codon which signals to the ribosome that translation commences at that point is:

Back 33

AUG - Methionine

Front 34

The main support to the DNA molecule is provided by two backbones which run along the two sides of the double helix. These backbones consist of

Back 34

sugars and phosphates linked together

Front 35

The process by which foreign DNA is introduced into a bacterium from the environment is known as translation.

Back 35

False