(Module 12) Reproduction

Question 1

What is the cell cycle

Answer 1

This is the process that all body cells use to grow and divide

Question 2

What are the differences between asexual reproduction and sexual reproduction (Definition wise)

Answer 2

Asexual reproduction only involves mitosis, and is where one cell divides and creates an exact copy of the cell
Sexual reproduction involves a male sex cell and female sex cell, and form a zygote

Question 3

Factors of sexual reproduction

Answer 3

2 parent cells, gametes (sperm an egg cell, egg cell and pollen), two gametes fuse together, mitosis, variation as dan from two parents

Question 4

Factors of asexual reproduction

Answer 4

1 parent cell, no gametes, divide by mitosis, no variation of offspring

Question 5

Factors of Mitosis

Answer 5

Takes place during growth and repair
Takes place in all cells except for gametes
It creates two daughter cells, with the same number of chromosomes
The daughter cells are clones, identical to the parent

Question 6

Factors of Meiosis

Answer 6

This takes place during the production of gametes (sex cells)
Takes place in reproductive organs
It produces four gametes
The daughter cells have half as many chromosomes
The daughter cells are genetically different from each other and the parent

Question 7

What is a gamete

Answer 7

This is a sex cell which unites with another sex cell to create a zygote. Contains only one set of chromosomes
Sperm for men, eggs for Women, pollen and seeds for plants

Question 8

What is DNA

Answer 8

DNA is a chemical found in the nucleus of cells, it is a polymer made up of two strands joined together.
The structure DNA is described as a double - stranded, double - helix molecule. DNA carries our genetic code

Question 9

What does DNA stand for

Answer 9

Deoxyribonucleic acid (DNA)

Question 10

What is a Gene

Answer 10

Genes are sections of Chromosomes (DNA) that code for a particular characteristic. Contains a code that codes for a particular sequence (chain) of amino acids
The chains of amino acids make a protein

Question 11

What are chromosomes

Answer 11

DNA is arranged in long coiled molecules called chromosomes. Each chromosome is composed of DNA and protein molecules (which hold the structure together)

Question 12

What is an Allele

Answer 12

Each gene has different forms, like different hair colours, and the different forms are called alleles

Question 13

What is a homozygote and a heterozygote

Answer 13

Homozygote- An individual with two identical alleles for a characteristic, such as BB or bb
Heterozygote- An individual with different alleles for a characteristic, for example Bb

Question 14

What is a genotype and a phenotype

Answer 14

Genotype- This describes the alleles present or genetic makeup of an individual regarding a particular characteristic, for example Bb or bb
Phenotype- This describes the physical appearance of an individual regarding a particular characteristic, for example black fur or brown fur in a mouse

Question 15

What are the differences between dominant alleles and recessive alleles

Answer 15

Dominant alleles are the alleles that are expressed/showed, even if there are only one dominant alleles, Bb
Recessive alleles are the alleles that is ‘marked’ by a dominant alleles. Recessive alleles are only expressed if they occur in pairs e.g bb, tt

Question 16

What is a pungent square

Answer 16

Its the way to work out what percentage there is of a person getting a certain allele
REVISE IT WITH IMAGES

Question 17

How many chromosomes are there in a normal human body/how many pairs
Extra: how many pairs of chromosomes are for general body characteristics

Answer 17

46 chromosomes, 23 pairs

Extra: There are 22 pairs for general characteristics, whilst the other pair is for what sex you are

Question 18

What determines the gender in terms of X AND Y, and what is the likelihood

Answer 18

50:50
A female egg cell contains the Allele X
A male sperm cell can have either X or Y
If it is XX, the baby is girl, and if it is XY, it is always a boy

Question 19

Why would scientists study the Human Genome?

Answer 19

• Search for genes linked to different types of diseases
• Understand and be able to treat inherited diseases
• Used in training human migration patterns from the past

Question 20

What is Polydactyl and what causes it ?

Answer 20

This is when a baby is born with extra fingers or toes
It is a dominant phenotype caused by a dominant allele
If a parent has polydactyl and are heterozygous, the child has a 50% chance of getting the inherited disorder

Question 21

What is Cystic Fibrosis and what causes it?

Answer 21

It is a genetic disorder prevents the movement of certain substances from side to the other, which lets cuscus become thick and sticky, clogging up areas like the lungs and the reproductive system
Caused by a recessive allele, so both parents must have it. 25% chance a kid has it

Question 22

What is an inherited disease

Answer 22

This is a disease that is caused by a result of a change in the coding of our genes passed on by parents to kids

Question 23

What is genetic screening/testing

Answer 23

This is undergoing tests to discover if a person/embryo/foetus has a genetic disorder or is carrying a faulty allele

Question 24

How can cells be harvested by embryos to be genetically scanned?

Answer 24

Amniocentesis- takes a sample of the fluid around the baby
Chorionic villus sampling- Sample of tissue surrounding the baby
Analysing foetal cells found in the mothers blood

Question 25

What are the advantages of Genetic Screening

Answer 25

• Decide whether or not to have children/continue with pregnancy
• Preparation- can plan ahead, and could get treatment for the condition
• They will know if there is a possibility of getting ill in the future

Question 26

What are the disadvantages of Genetic Screening

Answer 26

• Risk of miscarriage/harm to the mother foetus
• Tests might not be reliable (false positive/false negative) results
• Screening is very expensive
• Ethically or morally wrong in some religion