The Control Of Gene Expresion (3.8)

Question 1

When do gene mutations arise?

Answer 1

During DNA replication

Question 2

What are the types of gene mutation?

Answer 2

Addition, deletion, substitution, inversion, duplication, translocation of bases

Question 3

Gene mutations occur ____________.

Answer 3

Spontaneously

Question 4

What is a mutagenic agent?

Answer 4

Something that increases the rate of mutation

Question 5

What is an addition mutation?

Answer 5

Adding a nucleotide

Question 6

What is a deletion mutation?

Answer 6

Removing a nucleotide

Question 7

What is a substitution mutation?

Answer 7

Changing one nucleotide for another

Question 8

What is an inversion mutation?

Answer 8

A segment of a chromosome breaks off and reattaches elsewhere in the opposite direction

Question 9

What is a duplication mutation?

Answer 9

One or more copies of a DNA segment are produced

Question 10

What is a translocation mutation?

Answer 10

Moving of a section of DNA from one chromosome to another

Question 11

What is the definition of a mutation?

Answer 11

A change in the sequence of nucleotides/ bases in the DNA

Question 12

What processes produces new combinations of alleles?

Answer 12

crossing over

Independent segregation of homologous chromosomes

Random fertilisation

Question 13

What is a totipotent cell?

Answer 13

Stem cell

Question 14

Totipotent cells can divide and produce any type of body ____.

Answer 14

Cell

Question 15

Totipotent cells occur only for a ______ time in early mammalian embryos.

Answer 15

Limited

Question 16

Pluripotent stem cells can divide in u___________ numbers and can be used in treating human disorders.

Answer 16

Unlimited

Question 17

During embryonic development as new cells are made some of the genes are “switched off” (no longer transcribed). These cells are called _____________.

Answer 17

Pluripotent

Question 18

In adults cells are highly specialised and referred to as ____________ ie can differentiate a they divide into a limited number of cell types

Answer 18

Multipotent

Question 19

In eukaryotic cells when a gene is transcribed pre mRNA is made. What is the difference between pre mRNA and mRNA?

Answer 19

Pre mRNA contains introns and exons. MRNA only contains exons because the intros are spliced out

Question 20

What is the difference between the coding strand of a gene and pre mRNA?

Answer 20

DNA is made of nucleotides with the bases Adeneine, thymine, guanine and cytosine whereas in RNA is adenine, uracil, guanine and cytosine

The mRNA strand has as sequence of bases that is complementary to the sequence on the DNA rather than the same as. RNA nucleotides have the sugar ribose whereas DNA nucleotides have deoxyribose

Question 21

How does mRNA leave the nucleus?

Answer 21

Nuclear pores

Question 22

How many codons on mRNA attach to a ribosome during translation at any one time?

Answer 22

2

Question 23

What is the name of the bond formed between two amino acids in the polypeptide chain? What is needed for this bond to form?

Answer 23

Peptide
ATP is hydrolysed to release energy

Question 24

What happens to the polypeptide as it is being made?

Answer 24

It is folded and transported along the rough Endoplasmic reticulum