Chapter 3 - Genetics- Chromosomes/ Genes/ Alleles

Question 0

What do eukaryotic chromosomes form the basic structure of?

Answer 0

The nucleosome and packed together to form chromatin

Question 1

What are eukaryotic chromosome consist of?

Answer 1

DNA wrapped around histone proteins

Question 2

Eukaryotic chromosomes consist of DNA packed around histone proteins which is packed together to form chromatin- what does chromatin do during prophase and what does this allow?

Answer 2

Chromatin will supercool and condense during prophase which forms chromosomes that can be visualised under microscope

Question 3

Eukaryotic Has had DNA wrapped around proteins prokaryotic have?

Answer 3

Nothing wrapped around it=’naked’

Question 4

Definition of a gene

Answer 4

Unit of inheritance

Section of DNA that codes for protein

Question 5

Definition of an allele

Answer 5

Different versions of the same gene

Question 6

Definition of genome

Answer 6

Whole genetic information of an organism

Question 7

Definition of gene mutation

Answer 7

Change in the nucleotide sequence of a section of DNA coding for a particular feature

Question 8

What is the cause of sickle cell anaemia? And what does it do?

Answer 8

-base substitution mutation is a change of a single base sequence of DNA

Question 9

What does base substitution result in?

Answer 9

A change in a single mRNA condon during transcription

Question 10

In sickle cell anaemia what is the codon that is changed to result in the disease?

Answer 10

The 6th codon for the beta chain of haemoglobin is changed from GAG to GTG

Question 11

The change of GAG to GTG goes what regarding S.C.A?

Answer 11

Causes a change in mRNA codon (GAG to GUG) resulting in a single amino acid change of glutamic acid to valine (Glu to Val)

Question 12

So what does DNA change to?
What does mRNA change to?
What does amino acid change to?
All regard sickle cell anaemia

Answer 12

DNA = GAG to GTG
mRNA= GAG to GUG
Amino acid= Glu to Val

Question 13

What does the amino acid alter?

Regarding sickle cell anaemia

Answer 13

Alters shape of haemoglobin –> forms fibrous, insoluble strands–> red blood cells adopt a sickle cell shape

Question 14

What are the 3 bad consequences of sickle cell anaemia?

Answer 14

• insoluble haemoglobin chat effectively carry oxygen= weakness, shortness of breath and tiredness
• sickle cells may accumulate in the capillaries and form clots, blocking blood supply to vital organs and causing health problems
• causes anaemia (low RBC) as cells are destroyed more rapidly than normal RBC

Question 15

Who does sickle cell anaemia occur in? One is one benefit of being a carrier?

Answer 15

• it occurs in individualsb who have 2 copies of the co-dominant sickle cell allele
• heterozygous carriers have increased resistance to malaria