2- Simple Inheritence In Animals And Plants

Question 0

What is mitosis?

Answer 0

A-sexual cell division which results in two identical cells (with identical chromosomes) being produced from the original cell for growth and replacement
Each has a double set of chromosomes

Question 1

Why is cell division necessary?

Answer 1

For the growth of an organism or for the repair of damaged tissue

Question 2

What do chromosomes contain and what must happen to them and how?

Answer 2

Genes/alleles which mist be passed onto each new cell. A copy of the chromosome is made before the cells divide and one of each goes to a new cell

Question 3

What is a stem cell?

Answer 3

An unspecialised cell in the early development of animal and plant embryos (can change into any type of cell) found in human embryos and adult bone marrow

Question 4

What happens to cells before sexual reproduction?

Answer 4

They divide by meiosis to form sex cells (gametes) which has only one chromosome from each original pair and are all different from each other

Question 5

What happens to cells during sexual reproduction?

Answer 5

Gametes from each parent fuse resulting in variation of the father and mothers genetic information (half and half). The cell then divides by mitosis repeatedly to form a new individual

Question 6

What is meiosis?

Answer 6

The sexual two division process of cell division in the testes or ovaries resulting in four cells with a single set of chromosomes each to produce gametes

Question 7

How could stem cells benefit humans?

Answer 7

It is hoped they can be changed into different types of cells to then treat conditions such as paralysis

Question 8

Who was Gregor Mendel and why is he known?

Answer 8

He is a monk who was the first to suggest the idea of separately inherited genes, although it took along time before his idea was accepted because scientists did not knows about chromosomes

Question 9

What are chromosomes made of?

Answer 9

DNA which is a very long molecule with a double helix structure

Question 10

What are genes?

Answer 10

Short sections of DNA

Question 11

What is a gene code for?

Answer 11

Each gene codes for a particular combination of amino acids which make a specific protein

Question 12

How many pairs of chromosomes do humans have?

What chromosomes do males and females have?

Answer 12

23 pairs

Males have an X and a Y chromosome whereas females have two X chromosomes

Question 13

What is an allele?

Answer 13

Genes controlling the same characteristics

Question 14

What are the two types of allele and explain what they do?

Answer 14

Dominant alleles mask the effect of the another allele
Recessive alleles are masked by the effect of the dominant allele

Family trees illustrate inherited characteristics

Question 15

What are 1)phenotype and 2)genotype?

Answer 15

1) Physical appearance of the characteristics

2) the genetic make up

Question 16

What are 1)homozygous and 2)heterozygous?

Answer 16

1) both alleles are the same

2) the two alleles are different

Question 17

What happens when one dominant allele is inherited? Give an example

Answer 17

The person only has to inherit one dominant allele for it to be dominant on them (they will have the characteristic
Eg. Polydactyly (extra fingers or toes)

Question 18

What happens if someone inherits a recessive allele and give an example?

Answer 18

They need to inherit two recessive alleles for it to be dominant on them to have the characteristic. This means a child can receive the characteristic from two parents who are only carriers of it, and do not have it themselves
Eg. Cystic Fibrosis (thick sticky mucus that can affect organs)

Question 19

What is the most versatile stem cell and where is it found?

Answer 19

Embryonic stem cells, found in embryos, umbilical chords or adult cells

Question 20

Why are people concerned about the use of embryos in stem cell research?

Answer 20

Babies could be born if it was not being done
Research is experimental
It is very expensive

Question 21

What is embryo screening?

Answer 21

In IVF the embryos are screened to check there health, only healthy ones are implanted into the mother and the others destroyed