QUESTION 1 Cytosines and guanines are paired by 2 hydrogen bonds, while adenines

Question

QUESTION 1

Cytosines and guanines are paired by 2 hydrogen bonds, while adenines and thymines are paired by 3 hydrogen bonds.

True

False

1 points   

QUESTION 2

What are the 3 main components of a DNA nucleotide?

An alcohol functional group, a nitrogenous base, a deoxyribose

A phosphate group, a nitrogenous base, a ribose

A phosphate group, a nitrogenous base, a deoxyribose

An alcohol functional group, a nitrogenous base, a ribose

1 points   

QUESTION 3

Which of the following is incorrect?

Cytosine pairs with Guanine

Nucleotides in DNA consist of deoxyribose sugar, phosphate group and a nitrogenous base

Adenine pairs with Thymine

Two strands of DNA double helix are held together by covalent bonds

1 points   

QUESTION 4

The correct order of steps in a PCR cycle is:

Annealing, denaturation, extension

Annealing, extension, denaturation

Denaturation, annealing, extension

Extension, denaturation, annealing

1 points   

QUESTION 5

The goal of the polymerase chain reaction (PCR) is to:

Cleave DNA molecules

Digest bacterial plasmids

Amplify a small amount of DNA sequence

Sequence DNA

1 points   

QUESTION 6

Hydrogen bonds are weaker than covalent bonds. During PCR, hydrogen bonds are broken during the denaturation step.

True

False

1 points   

QUESTION 7

RNA differs from DNA in that it:

contains ribose sugar

contains uracil

is usually found as a single-stranded molecule in cells

all of the above

1 points   

QUESTION 8

At which temperature does a DNA double helix denature?

95

85

75

15

An alcohol functional group, a nitrogenous base, a deoxyribose

A phosphate group, a nitrogenous base, a ribose

A phosphate group, a nitrogenous base, a deoxyribose

An alcohol functional group, a nitrogenous base, a ribose

Explanation / Answer

1)- false. Because cytosine and guanine paired by 3 hydrogen bond and adenine and thymine are paired by 2 hydrogen bond.

2)--option c is correct because nucleotides contain phosphate group, nitrogenous bases, deoxyribose sugar.

3)-option d is correct because double stranded DNA are held together by hydrogen bond.

4)-option c is correct because there are 3 steps of PCR - denaturation,annealing and extension.

5)-option c is correct because PCR help to amplify the DNA sequence.

6)- true. Because in denaturation the double stranded DNA convert into single stranded DNA by breaking of hydrogen bond.

7)-option d is correct because RNA is single stranded strand, ribose sugar present and contain uracil base.

8)- option a is correct because at this temperature the double stranded DNA denature into single stranded DNA.

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