Chapter 3 - Genetics- Chromosomes/ Genes/ Alleles Flashcards Preview

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Flashcards in Chapter 3 - Genetics- Chromosomes/ Genes/ Alleles Deck (16)
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0
Q

What do eukaryotic chromosomes form the basic structure of?

A

The nucleosome and packed together to form chromatin

1
Q

What are eukaryotic chromosome consist of?

A

DNA wrapped around histone proteins

2
Q

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?

A

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

3
Q

Eukaryotic Has had DNA wrapped around proteins prokaryotic have?

A

Nothing wrapped around it=’naked’

4
Q

Definition of a gene

A

Unit of inheritance

Section of DNA that codes for protein

5
Q

Definition of an allele

A

Different versions of the same gene

6
Q

Definition of genome

A

Whole genetic information of an organism

7
Q

Definition of gene mutation

A

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

8
Q

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

A

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

9
Q

What does base substitution result in?

A

A change in a single mRNA condon during transcription

10
Q

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

A

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

11
Q

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

A

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

12
Q

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

A

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

13
Q

What does the amino acid alter?

Regarding sickle cell anaemia

A

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

14
Q

What are the 3 bad consequences of sickle cell anaemia?

A
  • 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
15
Q

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

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

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