Topic 7.3, 7.4, 7.5: DNA Replication, Transcription, Translation Flashcards Preview

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Flashcards in Topic 7.3, 7.4, 7.5: DNA Replication, Transcription, Translation Deck (46)
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1

What is the arrangement of nucleotides in a single DNA strand? S = sugar, P = phosphate group, B = organic base

 

A

2

Which group of three molecules make up one RNA nucleotide?

A. Phosphate, ribose, uracil

B. Phosphorus, ribose, adenine

C. Uracil, deoxyribose, phosphorus

D. Guanosine, deoxyribose, phosphate

A

3

Between which bases are hydrogen bonds formed in DNA?

A. C and U

B. T and G

C. A and T

D. U and A

C

4

What is the function of helicase?

A. It forms bonds between DNA nucleotides.

B. It adds new nucleotides to the DNA helix.

C. It forms the DNA helix.

D. It separates DNA strands.

D

5

Which is the variable part of the DNA nucleotide?

A. The sugar molecule

B. The phosphate molecule

C. The nitrogen base

D. The ribose molecule

C

6

A certain gene codes for a polypeptide that is 120 amino acids long. Approximately how many nucleotides long is the mRNA that codes for this polypeptide likely to be?

A. 30

B. 40

C. 360

D. 480

C

7

The codons CGU and CGC both code for the addition of the amino acid arginine to a growing polypeptide chain. What term is used to describe this property of the genetic code?

A. Universal

B. Degenerate

C. Redundant

D. Complementary

B

8

Draw a diagram showing the molecular structure of a section of the DNA molecule

two polymers shown; arranged in a double helix; sugar shown connected to base; sugar-phosphate backbone shown; If only one nucleotide is drawn, award [2 max] sugar identified as deoxyribose; hydrogen bonding between bases shown; diagram shows complementary base pairing / A bonded to T, C with G; Award previous mark if bases (unlabelled) are shown in the diagram but the complementary base pairing is explained in the annotation. covalent bonding between phosphate and sugar;

9

Outline the process of translation.

mRNA is used as a template / guide; mRNA “read” in base triplets / codon; each codon specifying addition of a particular amino acid to the growing polypeptide; ribosomes bind to mRNA / initiation ribosomes move along mRNA facilitating addition of amino acids / elongation tRNA bring amino acids (to mRNA-ribosome complex); tRNA has a complementary anti-codon; that binds to a specific codon; stop codon causes release of polypeptide / termination;

10

Which labels on the diagram are parts of a nucleotide?

A. I only

B. I and II only

C. II and IV only

D. I, II and III only

D

11

Which enzyme separates the strands of DNA during replication?

A. DNA polymerase

B. RNA polymerase

C. Reverse transcriptase

D. Helicase

D

12

Where do transcription and translation occur in eukaryotic cells?

                       Transcription                      Translation

A.                  Cytoplasm                           Cytoplasm

B.                  Cytoplasm                          Mitochondria

C.                 Nucleus                              Cytoplasm

D.                 Nucleus                               Nucleus

C

13

Living organisms use DNA as their genetic material. Explain how DNA is replicated within the cells of living organisms.

helix is unwound; two strands are separated; helicase (is the enzyme that unwinds the helix separating the two strands); by breaking hydrogen bonds between bases; new strands formed on each of the two single strands; nucleotides added to form new strands; complementary base pairing; A to T and G to C; DNA polymerase forms the new complementary strands; replication is semi-conservative; each of the DNA molecules formed has one old and one new strand; 

14

Which substance is a base that is found in DNA?

A. Adenosine

B. Cytokinin

C. Guanine

D. Uracil

C

15

Which two processes involve the unwinding (uncoiling) of the DNA double helix and its separation into two strands of nucleotides?

A. Replication and telophase of mitosis

B. Telophase of mitosis and translation

C. Translation and transcription

D. Transcription and replication 

D

16

What is a possible consequence of two base substitution mutations occurring in the same gene?

A. Two amino acids coded for by the gene are changed.

B. Amino acids in two polypeptides coded for by the gene are changed.

C. All of the codons between the two mutations are changed.

D. All of the codons from the first mutation onward are changed.

A

17

The diagram below represents a DNA nucleotide. What could the part labelled X represent?

A. Ribose

B. Uracil

C. Guanine

D. Phosphate

C

18

In the structure of DNA what binds with cytosine?

A. Deoxyribose

B. Ribose

C. Thymine

D. Adenine

A

19

What is responsible for the conservation of the base sequence during DNA replication?

A. DNA polymerase working on one strand at the same time.

B. Unpaired bases always attracting their complementary nucleotides.

C. DNA helicase and polymerase are complementary.

D. Both strands are identical to each other.

B

20

Explain the process of translation.

messenger / mRNA attaches to ribosome (small unit); many ribosome/polyribosomes bind to same mRNA; carries codons / triplet of bases each coding for one amino acid; transfer / tRNA each have specific anticodon; triplet of bases for specific amino acid; tRNA carries specific amino acid; tRNA binds to ribosomes; to corresponding triplet base / codon; a second tRNA binds to next codon; two amino acids bind together; in a peptide linkage; first tRNA detaches; ribosome moves along mRNA; another tRNA binds to next codon; continues until polypeptide / protein formed to stop codon; stop codon has no corresponding tRNA/amino acid / causes release of polypeptide; 

21

During the process of replication, which bond(s) in the diagram of DNA below is/are broken?

A. 3

B. 4, 5

C. 1, 2, 6, 7

D. 1, 7, 4, 5

B

22

Draw and label a simple diagram to show how DNA is constructed from sugars, phosphates and bases.

Award [1] for each of the following clearly drawn and correctly labelled. labelled phosphate linked to labelled sugar by a single bond; labelled base linked to a labelled sugar by a single bond; correctly linked base, sugar and phosphate labelled as nucleotide; covalent bond(s) labelled between sugar and phosphate/between sugar and base; at least two nucleotides linked by a single sugar-phosphate bond; at least two nucleotides linked by base-base bonds; hydrogen bonds labelled between bases; A-T and/or G-C base pairing; phosphate and base shown linked to correct carbon atoms on sugar; 

23

Draw and label a diagram of the molecular structure of DNA.

Award [1] for each of the following clearly drawn and correctly labelled. nucleotide sub-units; composed of sugar-phosphate-base; sugar is deoxyribose; hydrogen bonds between bases; A-T and C-G base pairing; sugar-phosphate backbone; covalent bonds between sugar and phosphate / between sugar and base; helical structure appropriately drawn; (label not required) double-stranded appropriately drawn; (label not required)

24

Compare the structure and composition of DNA with RNA

Direct comparisons must be made to achieve a mark. both are polymers of nucleotides / both are nucleic acids; sugar is deoxyribose in DNA whereas ribose in RNA; DNA is double stranded whereas RNA is single stranded; DNA contains thymine whereas RNA contains uracil; complementary base pairing involved in DNA but not in RNA; both contain four nitrogenous bases; 

25

Describe the roles of mRNA, tRNA and ribosomes in translation.

mRNA with genetic code / codons; tRNA with anticodon; tRNA with amino acid attached; ribosome with two sub-units; mRNA held by ribosome; start codon; two tRNA molecules attached with mRNA on ribosome; peptide bond between amino acids on tRNA; polypeptide forms; ribosome moves down mRNA; continues until a stop codon is reached; polypeptide is released;

26

What is true about eukaryotic DNA?

A. It contains the complementary base pair adenine-uracil.

B. It is naked.

C. The majority consists of repetitive sequences.

D. The majority codes for genes.

C

27

What is removed to form mature eukaryotic mRNA?

A. RNA primers

B. Exons

C. RNA polymerases

D. Introns

D

28

Which enzymes are needed to produce recombinant plasmids that are used in gene transfer?

A. DNA polymerase and ligase

B. DNA polymerase and restriction enzymes

C. Restriction enzymes and ligase

D. Helicase and restriction enzymes

C

29

Which molecule is involved in the process of transcription?

A. DNA polymerase

B. Helicase

C. DNA ligase

D. mRNA 

D

30

What is the composition of the backbone of DNA?

A. Alternating sugar and phosphate molecules

B. Complementary base pairs

C. Alternating sugar and base molecules

D. A polysaccharide

A

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