Genetics

Question 1

What is meiosis?

Answer 1

Occurs in reproductive cells. Daughter cells have half the number of chromosomes. (E.g. 23 vs 46). The cell replicates itself and then splits the DNA to form 4 gametes.

Question 2

What is a homozygous gene?

Answer 2

2 copies of a gene that are identical

Question 3

What is a heterozygous gene?

Answer 3

2 copies of the same gene that are different.

Question 4

What is an allele?

Answer 4

An alternative form of the same gene located on homologous chromosomes at identical locations.

Question 5

What is a genotype and phenotype?

Answer 5

Genotype- the genetic makeup of an organism

Phenotype- the physical characteristics resulting from the genotype

Question 6

What are dominant and recessive genes?

Answer 6

A dominant gene is a gene that is expressed in the phenotype. The recessive gene is a gene that is masked by the other gene

Question 7

What are the components of the DNA structure?

Answer 7

Phosphate which is connected to deoxyribose sugar which is connected to the nitrogenous bases.

Question 8

What are the 4 nitrogenous bases?

Answer 8

T- thymine
A- adenine
C- cytosine
G- guanine

Question 9

What is a chromosomal abnormality?

Answer 9

A mutation that occurs in the chromosomes during meiosis and results in too many or too little chromosomes.

Question 10

What is a gene abnormality?

Answer 10

When a mutation occurs in the DNA and the gene doesn’t code for the correct amino acid/protein

Question 11

What are the three ways to alter a gene?

Answer 11

Adding a foreign gene, altering an existing gene or deleting a gene

Question 12

What is adding a foreign gene and example?

Answer 12

A gene from another species is inserted into the organism so the GMO expresses the traits of that species (transgenic). E.g. Glow in the dark rabbits with a gene from a jellyfish.

Question 13

What is altering an existing gene?

Answer 13

Making the gene express in a different way or at a higher level. E.g. Making growth hormones express more so the organism grows more.

Question 14

What is deleting a gene? Example

Answer 14

Deactivating an existing gene to prevent the expression of that trait. E.g. Deactivation of tomato ripening gene for a longer shelf life.

Question 15

What is mitosis?

Answer 15

Cell replication in all cells except reproductive cells. The cell replicates itself and then splits to form 2 identical cells.

Question 16

Who were the 4 people who helped discover DNA structure?

Answer 16

Rosalind Franklin *
Maurice Wilkins *
James Watson ^
Francis Crick ^

Question 17

What did Franklin and Wilkins do?

Answer 17

They were crystallographers who took photos of DNA. Photograph 51 helped discover the DNA structure

Question 18

What did Watson and Crick do?

Answer 18

They used photograph 51 to determine that the structure of DNA was a double helix

Question 19

What did Gregor Mendel do?

Answer 19

He was a monk who did experiments cross breeding peas to determine patterns of inheritance and dominant and recessive genes.

Question 20

What happens in DNA replication?

Answer 20

The double helix unzips and nucleotides from the cytoplasm join to form 2 new double helixes

Question 21

What causes Down Syndrome?

Answer 21

It is a chromosomal abnormality that happens when meiosis doesn’t work properly and the 21st chromosome doesn’t split properly, causing someone to have 3 21 chromosomes

Question 22

What are arguments for GM?

Answer 22

Increase in food production- improves nutrition of people
Decrease in use of pesticides
Economic benefits

Question 23

What are arguments against GM?

Answer 23

Transgenic organisms spreading uncontrollably in the wild
Makes GM animals unhealthy
May cause resistance to pests or insects
Economic impacts/no benefits to farmers

Question 24

What is gene therapy?

Answer 24

Where the defective gene is replaced with a properly working gene

Question 25

What is the process of gene splicing?

Answer 25

Remove plasmid and cut it using enzyme
DNA is cut to isolate a gene
Join both to form gene
Implant gene inside bacteria to reproduce