Question

When the structure of a DNA molecule is compared to a ladder, the uprights of the ladder are composed of

		sugars.
		phosphates.
		purine-pyrimidine pairs.

If a DNA molecule containing the base sequence 5 CAGTTA 3 unzipped during replication, and replication that occurred in the direction away from the replication fork (to right) and proceeded in three-base sequences, what would be the FIRST three-base sequence to be formed?

		5 TTA 3
		5 CAG 3
		3 TTA 5
		3 GTC 5
		5 AAT 3

Introns occur only rarely in

		animals.
		plants.
		fungi.
		bacteria.

Halley is studying differences between human DNA and starfish DNA. Where might she find the greatest differences?

		phosphates
		ribose
		deoxyribose
		bases
		amino acids

The term ______________ explains a post-transcriptional gene regulation mechanism in eukaryotes in which multiple protein products are produced by a single gene.

		mutation repair
		alternative splicing
		epigenetics
		gene expression

DNA replicates by which of the following models?

		conservative
		semiconservative
		dispersive
		none of the choices is correct

If a DNA molecule contained the base sequence 5 TATCGTC 3 unzipped for replication, what would be the sequence of its complementary NEW strand?

		5 ATAGCTG 3
		5 ATAGCAG 3
		3 ATAGCTG 3
		5 ATAGTAG 3
		3 ATAGCAG 5

When the structure of a DNA molecule is compared to a ladder, the uprights of the ladder are composed of

		phosphates.
		purine-pyrimidine pairs.
		sugars.

The term ___________ explains the process of removing introns and reconnecting exons in a pre-mRNA.

		splicing
		DNA repair
		incision
		excision

An unspliced RNA molecule is called

		proto-RNA.
		mRNA.
		pre-mRNA.
		post transcript.

Answer 1

Answer:

1). Purine-pyrimidine pairs

Explanation:

The shape of DNA is a double helix, which is like a twisted ladder. The sides of the ladder are made of alternating sugar and phosphate molecules. The sugar is deoxyribose. The rungs of the ladder are pairs of 4 types of nitrogen bases. A=T & G=C pairs.

2). 3 GTC 5

Explanation:

Adenine (A) pairs with thymine (T) and vice versa.

Guanine (G) pairs with cytosine (C) and vice versa.

3’ = 5’ and vice versa.

3). Bacterial

Explanation:

Introns are well known in bacterial and archaeal genes, but occur more rarely than in most eukaryotic genomes.

4). Bases

Explanation:

Each DNA consists of deoxyribose, phosphate and nitrogen bases. Deoxyribose and phosphate are similar but number of bases is different in both the species.

5). alternative splicing

6). Semiconservative

Explanation:

Semiconservative replication would produce two copies that each contained one of the original strands and one new strand

7). 3 ATAGCAG 5

Explanation:

5 TATCGTC 3

3 ATAGCAG 5

8). Splicing

Explanation:

Introns are non-protein coding genes, so that they are removed before the mRNA enters into the translation, by a process called splicing.

9). pre-mRNA.

Explanation:

mRNA that was transcribe from DNA is called pre-mRNA, which contains introns and exons. Introns are removed by splicing and then the mRNA consists of one exons that is called mature mRNA.