Question

TRUE/FALSE.

1. In a repressible operon transcription is normally turned off.

2) A Monoybrid cross involves one gene and two or more different alleles.

3) Crossing over during meiosis occurs in the Metaphase II stage.

4) In prokaryotes, transcription and translation are separated in time and space.

5) Crossing over takes place in meiosis and is responsible for recombination.

6) Natural selection can lead to a decrease in genetic variation both within and between populations.

7) The pyrimidine bases in nucleic acids are adenine and guanine.

8) The poly(A) tails on mRNA molecules are transcribed from DNA templates.

9) Exons are degraded in the nucleus. 10) Most DNA binding motifs, such as leucine zippers, and Zinc fingers, have the binding the major groove of DNA. site in

Answer 1

1. In a repressible operon transcription is normally turned off.

False

Transcription normally occurs in a repressible operon. Transcription is turned off either by the repressor becoming active in a negative repressible operon or by the activator becoming inactive in a positive repressible operon.

2) A Monoybrid cross involves one gene and two or more different alleles.

True

3) Crossing over during meiosis occurs in the Metaphase II stage.

False

Crossing over occurs between prophase 1 and metaphase 1 of meiosis

4) In prokaryotes, transcription and translation are separated in time and space.

False

Since prokaryotes do not have nuclear membrane, transcription and translation are not separated in time and space.

5) Crossing over takes place in meiosis and is responsible for recombination.

True

6) Natural selection can lead to a decrease in genetic variation both within and between populations.

True

Natural selection can decrease the genetic variation in populations of organisms by selecting for or against a specific gene or gene combination (leading to directional selection)

7) The pyrimidine bases in nucleic acids are adenine and guanine.

False

adenine and guanine are purine

Cytosine and thymine are pyrimidines

8) The poly(A) tails on mRNA molecules are transcribed from DNA templates.

False

a poly(A) tail is added to an RNA at the end of transcription

9) Exons are degraded in the nucleus.

False

Introns are sliced of during maturation of pre-mRNA

10) Most DNA binding motifs, such as leucine zippers, and Zinc fingers, have the binding the major groove of DNA. site in

True

These motifs generally use either ? helices or ? sheets to bind to the major groove of DNA