Chapter 3- Inheritance

Question 1

What are gametes ?

Answer 1

Haploid so contain one allele of each gene

Question 2

What does the fusion of gametes result in?

Answer 2

In diploid zygote with two alleles of each gene that may be the same allele or different alleles

Question 3

What are the three alleles for ABO blood groups?

Answer 3

I^ A
I ^ B
i

Question 4

What is segregation?

Answer 4

Separation of alleles into different nuclei - the two alleles of each gene separate into different haploid daughter nuclei during meiosis

Question 5

What can alleles be?

Answer 5

Dominant, recessive or co-dominant

Question 6

What are dominant and recessive alleles?

Answer 6

Recessive alleles are only shown id the dominant allele is not present

Question 7

What is a co-dominant allele

Answer 7

Where both alleles have an affect of the phenotype characteristic of the organism

Question 8

Ex of co-dominance

Answer 8

Flower colour in Mirabilis Jalapa - red flower mixed with white flowers offspring have pink flower

Question 9

Definition of genotype?

Answer 9

Symbolic representation of a pair of alleles possessed by an organism

Question 10

What is a phenotype?

Answer 10

The set of observable characteristics resulting from the interaction of genotype

Question 11

What does genotype I^A I^A five? What does I^B I^B give?
What does i i give?
What does I^A I^B give?

Answer 11

1) blood group A
2) blood group B
3) blood group O
4) blood group AB - co dominant

Question 12

Antigen A has what type of antibodies?

What type of blood can’t it have?

Answer 12

Antibodies b and can’t have b or ab blood but can O or A blood

Question 13

Antigen b what type of antibodies does It have?

What type of blood can’t it have?

Answer 13

Has anti- a antibodies and can’t have a or ab blood but can have b or o blood

Question 14

WHat type of antibodies does antigen AB have?

What type of blood can’t it have?

Answer 14

Doesn’t have antigens but can have any blood type- universal recipient

Question 15

What types of antibodies has A and B?

What type of blood can it only have?

Answer 15

Has both A and B antibodies and can only have O blood in it- universal donor

Question 16

Define test cross

Answer 16

Testing a suspected heterozygous by crossing it with a homozygous recessive

Question 17

What are many genetic diseases in humans caused by?

Answer 17

Due to recessive alleles of Autosomal genes

Question 18

What are other causes of genetic disease?

Answer 18

Some genetic diseases are sex-linked and some are due to dominant or xo-dominant alleles

Question 19

What is an example of a disease caused by recessive alleles?

Answer 19

Cystic fibrosis

Question 20

What is an example of a disease caused by a dominant allele?

Answer 20

Hunting tons disease

Question 21

What is an example of co-dominant allele?

Answer 21

Sickle-cell anaemia- HB^A and HB^S has some characteristics of sickle cell anaemia without having the disease- resistance to malaria

Question 22

What is sex linkage?

Answer 22

Any genetic trait whose allele has its logs on the X chromosome

Question 23

What is cystic fibrosis? What are its consequences?

Answer 23

It is a recessive allele that results in chloride channels being produced that do not function properly- causes production of abnormally thick mucus which builds up in lungs causing infections

Question 24

What is huntingtin disease?

Answer 24

Dominant allele of the HTT gene- causes degenerative changes in be brain - changes to behaviour, thinking and emotions become increasingly severe - life expectancy is about 20 years after symptoms

Question 25

What are examples of X-linked recessive conditions?

Answer 25

Colour blindness and haemophilia

Question 26

Where is the gene lock found for colour blindness / haemophilia ? Why does that mean men can’t carry it?

Answer 26

On the non-homologous region of the X chromosome (not present on Y) - as males only have one allele of this gene (one one X chromosome ) they cannot carry it- either express it or don’t have it

Question 27

What does males have a higher frequency of? Where do makes inherit X linked recessive conditions?

Answer 27

Of being recessive and expressing a trait

Mothers

Question 28

What are some causes of mutations?

Answer 28

Radiation and mutagenic chemicals increase the mutation rate and can cause genetic disease and cancer

Question 29

How does radiation cause mutation?

Answer 29

Increases the mutation rate if it has enough energy to cause chemical changes in DNA - gamma rays , alpha Ray’s etc all mutagenic

Question 30

How do chemical substances cause mutation?

Answer 30

Cause chemical changes to DNA and so are mutagenic ex: and nitrosamines found in tobacco smoke

Question 31

What are some on the consequences of the Hiroshima and Nagasaki bombs?

Answer 31

People either died directly or within a few months
Health of nearly 100,000 survivors have been monitored - many developed tumours
Led to many still births and malformations

Question 32

What are some of the consequences at Chernobyl in 1986?

Answer 32

Pine for forests turned ginger brown and died

Horses and cattle near the plant died of damage to thyroid gland

Question 33

What did Mendel discover?

Answer 33

Discovered the principles of inheritance with experiments in which large numbers of pea plants were crossed