Topic 3: Genetics

Question 1

What does meiosis produce?

Answer 1

4 genetically different haploid daughter cells (gametes)

Question 2

What are the main processes in meiosis?

Answer 2

1)Interphase-chromosomes duplicate
2)Chromosomes mix up and cell splits into 2
3)Cell splits into 4 genetically different haploid cells

Question 3

Why is the fruit mashed during DNA extraction?

Answer 3

Breaks apart the cells from each other and breaks down the cell walls

Question 4

What is the role of the salt during DNA extraction?

Answer 4

DNA is more likely to clump together in the final stage

Question 5

What is the role of the detergent during DNA extraction?

Answer 5

Ruptures (bursts) the cell membrane

Question 6

What does the added protease do during DNA extraction?

Answer 6

Its an enzyme that breaks down the proteins holding DNA together- causing the DNA to uncoil

Question 7

Why is it important to use ice cold ethanol during DNA extraction?

Answer 7

Slows down the action of enzymes- precipitates DNA

Question 8

What is DNA’s structure?

Answer 8

A double helix structure made up of DNA nucleotides

Question 9

What are nucleotides made up of?

Answer 9

1)Base
2)Sugar
3)Phosphate

Question 10

What are DNA bases bonded by?

Answer 10

Weak hydrogen bonds

Question 11

What are DNA complementary base pairs?

Answer 11

A-T
C-G

Question 12

What is a genetic code?

Answer 12

Sequence of bases

Question 13

What is a gene?

Answer 13

Segment of DNA containing instructions for protein

Question 14

What did Erwin Chargaff discover and how?

Answer 14

-Used chromatography
-Discovered that the ratio of A-T and C-G bases are equal

Question 15

What did Rosalin Franklin discover and how?

Answer 15

-Used x-rays
-Discovered DNA’s helix structure

Question 16

What are the two processes involved in protein synthesis?

Answer 16

-Transcription
-Translation

Question 17

What is a protein?

Answer 17

Polymer made from amino acids

Question 18

What is a polymer?

Answer 18

Long molecule made by chaining together many shorter ones

Question 19

What are the steps in transcription?

Answer 19

1)Enzyme names RNA polymerase binds with the non-coding region in DNA
2)Enzyme causes DNA to unwind
3)Nucleotides carry out complementary base pairing with the template strand to form mRNA
4)mRNA leaves the nucleus through nuclear pores

Question 20

What are the steps in translation?

Answer 20

1)mRNA enters the cytoplasm and binds to ribosome inside
2)Bases are read triplets at a time (codons)
3)tRNA carries amino acids
4)Anticodons on tRNA complementary base pair (or match) with codons on mRNA
5)Amino acids left behind are joined together by ribosomes to form a polypeptide chain
6)The polypeptide folds to form a protein

Question 21

What is mutation?

Answer 21

Change in a nucleotide base sequence of a DNA molecule

Question 22

What are the types of mutation?

Answer 22

-Insertion
-Deletion
-Substitution

Question 23

What causes mutation?

Answer 23

-Error in DNA replication
-Exposure to mutagens (substances that damage DNA)

Question 24

What effects does mutation have in amino acid sequences

Answer 24

-No change
-Shortens the protein
-Alters the protein made

Question 25

What effects does mutation have on protein function?

Answer 25

-No change -Reduced protein activity -Increased protein activity (rare) -Altered protein function

Question 26

What is an allele?

Answer 26

Different versions of the same gene

Question 27

What is a dominant allele?

Answer 27

Expressed when an individual has either 1 or 2 copies of that allele in their genotype

Question 28

What is a recessive allele?

Answer 28

Only expressed when an individual has 2 copies of that allele in their genotype

Question 29

What is a genotype?

Answer 29

The specific combination of alleles an individual inherits

Question 30

What is a phenotype?

Answer 30

The observable/expressed traits that result from an individuals genotype

Question 31

What does homozygous mean?

Answer 31

Both alleles for one gene are the same

Question 32

What does heterozygous mean?

Answer 32

Alleles in a gene are different from each other

Question 33

What are the symptoms of sickle cell disease?

Answer 33

-Tired/shortness of breath -Blood clots -Painful joints

Question 34

What does cystic fibrosis cause?

Answer 34

Over production of mucus in the body-thick and sticky

Question 35

What is an antigen?

Answer 35

A marker that tells your immune system whether something is harmful or not

Question 36

What blood types are there?

Answer 36

-A -B -O

Question 37

What does the ABO blood system involve?

Answer 37

One immunoglobulin gene which has 3 different alleles: -Type A-codes for antigenA -Type B-codes for antigenB -Type O-codes for nothing

Question 38

What is codominance?

Answer 38

The equal expression of both alleles in the phenotype, rather than one allele being dominant

Question 39

What are the sex chromosomes for males and females?

Answer 39

Female: XX Male: XY

Question 40

What are sex-linked disorders?

Answer 40

Characteristics influenced by genes carried on the sex chromosomes (mainly x- chromosomes)

Question 41

What is haemophilia?

Answer 41

A blood-clotting disorder caused by mutations on X-chromosomes

Question 42

Why are men more likely to inherit sex-linked disorders?

Answer 42

Males have a smaller Y chromosome than X meaning if just the X-chromosome had a disease, there wouldn't be another X to mask it and he would definitely have the disease

Question 43

What is variation?

Answer 43

The differences or diversity within a set of data observation

Question 44

What are the 2 types of variation?

Answer 44

-Genetic -Environmental

Question 45

What is continuous variation?

Answer 45

Traits showing full range of values within a population with a gradual change. E.G, height. weight

Question 46

What is discontinuous variation?

Answer 46

Traits that fall into distinct, separate categories. E.G, blood type, eye colour, gender