Genes & Genome

Question 1

Define Genome

Answer 1

All the DNA of an organism

Question 2

Since when do humans have their genome?

Answer 2

Since fertilisation

Question 3

What are the three main types of DNA?

Answer 3

Nuclear DNA, mitochondrial DNA, and Chloroplast DNA

Question 4

What are possible traits of nucleotide sequences?

Answer 4

They are genes
Regulatory (on/off)
Non-coding (Introns)
Tandem Repeats (repetitive)

Question 5

What is a Gene?

Answer 5

A heritable factor that consists of DNA and influences specific characteristics
OR
A sequence of DNA nucleotides that codes for a RNA or protein product

Question 6

Define Locus

Answer 6

A specific location on a chromosome where a gene is located
OR
A specific location on a gene

Question 7

Define allele

Answer 7

A different variation of the same gene

Question 8

Give an example of an alelle

Answer 8

A gene encodes for the eye Color brown, dependent on the parents, the alternative code may be for blue eyes

Question 9

How are new alleles formed?

Answer 9

Through mutations

Question 10

What is a chromosome

Answer 10

Supercooled DNA and associated structural proteins

Question 11

What is chromatin

Answer 11

A string of DNA wrapped around histone proteins

Question 12

What is Gene expression

Answer 12

The process by which a gene creates a product

Question 13

When is the X shape of a chromosome seen?

Answer 13

Only seen in prophase and metaphase when a cell has replicated its DNA and is dividing.

Question 14

What does a chromosome look like when its not dividing?

Answer 14

Like one leg of a chromosome pair

Question 15

Letters for homozygous dominant

Answer 15

AA

Question 16

Letters for heterozygous

Answer 16

Aa

Question 17

Letters for homozygous recessive

Answer 17

Aa

Question 18

How are alleles of the same gene the same?

Answer 18

They are the same gene and both code for the same type of protein(eg hair Color). They occupy the same locus on homologous (similar) chromosomes and the majority of the sequence remains the same between alleles.

Question 19

How do alleles differ from one another?

Answer 19

They base sequence is slightly different

Question 20

Which gene and corresponding protein is cystic fibroses controlled by?

Answer 20

The CFTR gene and Chloride ion channel protein

Question 20

What mutation is sickle cell disease caused by?

Answer 20

Mutation in the hemoglobin-beta gene

Question 21

What does a RBC experiencing sickle cell disease look like?

Answer 21

Like a half moon

Question 22

Why did the hemoglobin-beta gene mutate?

Answer 22

First it was an adaption to malaria (so that the virus cannot sit on the RBC).

Question 23

What is the issue with sickle cell anemia?

Answer 23

Oxygen cannot sit well on the half moon RBC, the life span of RBC is shorter so they die quicker and clotting occurs at a much higher rate.

Question 24

How many copies of chromosomes do eukaryotes have?

Answer 24

At least two. Meaning individuals have two alleles that may be the same or different

Question 25

What are mutations?

Answer 25

Changes to the base pair sequence of the organisms genetic code

Question 26

What is a germline cell?

Answer 26

One that gives rise to gametes(eg. egg or sperm cells)

Question 27

What happens when a mutation occurs in a germline cell?

Answer 27

The mutation can be passed on to offspring

Question 28

What is a body cell called?

Answer 28

Somatic

Question 29

What happens when a mutation occurs in a somatic cell?

Answer 29

Mutations are passed on to daughter cells during mitosis but are not passed on to offspring. An example includes cancer.

Question 30

Describe a spontaneous mutation.

Answer 30

A mutation that arises naturally and not as a result of exposure to mutagens. They occur due to errors in DNA replication

Question 31

List a few examples of mutagens

Answer 31

UV light Radiation(hiroshima) Cigarettes Radioactive substances X-Rays

Question 32

What is the cause of physical mutation

Answer 32

Exposure to radiation that damages the DNA

Question 33

What is the cause of chemical mutation

Answer 33

exposure to chemicals (eg. heavy metal ions) that damage the DNA

Question 34

What is biological mutation?

Answer 34

Viruses that insert themselves into host DNA

Question 35

When did Hiroshima happen?

Answer 35

1945

Question 36

What was hiroshima

Answer 36

the US detonated two atomic bombs over Japan. Between 100,000-200,000 thousand people died. Many thousands died prematurely over the years due to radiation-induced cancer/ mutations in DNA. Second-generation bomb victims experience mutations.

Question 37

When did Chernobyl happen?

Answer 37

1986

Question 38

What is silent mutation?

Answer 38

There is no change to the polypeptide sequence

Question 38

What was Chernobyl?

Answer 38

Due to a flawed reactor design of not properly trained personnel. The plant released many radioactive isotopes into the atmosphere, polluting over 200,000 km^2. Instant effects were dizziness, fatigue, and vomiting. Long-term physiological consequences affected antioxidants, hormones and immunity. Long-term physical effects were leukaemia and cardiovascular diseases.

Question 39

What is missense mutation?

Answer 39

A single amino acid is changed

Question 40

What is nonsense mutation?

Answer 40

A stop codon is created, polypeptide sequence is stunted

Question 41

Explain why a horse(64 chr. pairs) and a donkey(62. chr. pairs) have offspring with 63 pairs? And what does this mean?

Answer 41

Because the left over chromosomes pair up. This number is uneven so the offspring is infertile.

Question 42

How is DNA structured/ organized?

Answer 42

With nucleoide arrangement, phosphate, pentose sugar, base. The shape is a helix

Question 43

What is the uncoiled structure of a chromosome?

Answer 43

A single double-stranded helix.

Question 44

When are chromosomes homologous pairs?

Answer 44

When maternal and paterna; chromosomes align during fertilization