B13: Reproduction

Question 1

Why is there no variation in offspring that are made as a product of asexual reproduction?

Answer 1

There is no fusion of special sex cells (gametes).

Question 2

How does asexual reproduction work?

Answer 2

Cells divide by mitosis

Question 3

What are produced as a result of asexual reproduction?

Answer 3

Identical offspring (clones)

Question 4

In what is asexual reproduction very common?

Answer 4

The smallest animals and plants (plants like daffodils, strawberries and brambles too)

Question 5

What does sexual reproduction involve?

Answer 5

A male sex cell and a female sex cell fusing together to form a zygote, which develops to form a new individual

Question 6

How are gametes formed?

Answer 6

Through meiosis

Question 7

What happens during meiosis?

Answer 7

The chromosome number halves, so there are two sets of each chromosome inherited from the mother and one from the father.

Question 8

What are the gametes in plants?

Answer 8

Egg cells and pollen

Question 9

What are the gametes in animals?

Answer 9

Egg cells and sperm

Question 10

What happens when a cell divides to form gametes?

Answer 10

The genetic info is copied so there are 4 sets of each chromosome. Each chromosome forms a pair of chromatids.
The cell then divides twice to form four gametes, each with a single set of chromosomes.

Question 11

What are the advantages of asexual reproduction?

Answer 11

-only one parent needed
-faster than sexual reproduction

Question 12

What are the disadvantages of asexual reproduction?

Answer 12

-If one organism cannot survive, none can.

Question 13

What are the disadvantages of sexual reproduction?

Answer 13

-two parents needed
-slower than asexual reproduction

Question 14

What are the advantages of sexual reproduction?

Answer 14

-the variation means if the environment changes, they wont go extinct.

Question 15

What is the most common form of reproduction in fungi?

Answer 15

Asexual

Question 16

In what conditions do some fungi reproduce sexually?

Answer 16

In dry conditions

Question 17

What are some examples of asexual reproduction in plants?

Answer 17

Strawberry plants, spider plants, daffodils

Question 18

What is DNA?

Answer 18

A long molecule made up of many repeating units

Question 19

What are genes?

Answer 19

Small sections of DNA

Question 20

Put the parts of DNA in size order?

Answer 20

DNA > chromosome > gene > sequence of amino acids that make a specific protein

Question 21

What is a genome?

Answer 21

The entire genetic material of the organism

Question 22

Why is learning more about the human genome important?

Answer 22

-Helps us understand inherited disorders (cystic fibrosis, sickle cell)
-helps us search for genes linked to different diseases
Helps us pick the best treatment for cancers for each individual
-helps us understand human evolution and history

Question 23

The long strands of DNA are made up of alternating ——- and ———— sections.

Answer 23

Sugar and phosphate sections.

Question 24

What 4 letters represent the bases in DNA?

Answer 24

A,C,G & T

Question 25

What is the combination of a sugar, a phosphate and a base called?

Answer 25

A nucleotide

Question 26

How many nucleotides are in a group?

Answer 26

3

Question 27

Each group of - bases codes for a particular ——— ———.

Answer 27

3, amino acids

Question 28

A change or mutation can ———— or ———- the whole protein structure and the way it works.

Answer 28

Change or disrupt

Question 29

In what pairs do the base letters couple up with each other?

Answer 29

C&G. T&A

Question 30

How are proteins made from DNA?

Answer 30

1. Genes in the DNA produce a template for the protein. It reflects the sequence of bases in DNA. 2.the template leaves the nucleus and binds to the surface of a ribosome. 3. The cytoplasm contains carrier molecules that are attached to an amino acid. 4. The CMs attach themselves to the template. 5. The amino acids are joined together to form a specific protein. 6. CMs keep bringing AAs to add to the protein chains until the template is completed. 7. protein detaches from the CMs and the CMs detach from the template and go back to cytoplasm to get more AAs.

Question 31

When is a gene said to be expressed?

Answer 31

When a gene codes for a protein that is synthesised in the cell

Question 32

What is one thing that scientists have discovered that the non-coding parts of DNA do?

Answer 32

Switching genes on and off.

Question 33

What are mutations?

Answer 33

Changes in existing genes

Question 34

What can happen as a result of mutations?

Answer 34

-the active site changing shape and an enzyme losing its strength - the active site changing shape and an enzyme becoming stronger

Question 35

What does homozygote mean?

Answer 35

An individual with two identical alleles for a characteristic (e.g. BB or bb)

Question 36

What does heterozygote mean?

Answer 36

An individual with different alleles for a characteristic (e.g. Bb)

Question 37

What does genotype mean?

Answer 37

It describes the alleles present or genetic makeup of an individual regarding a particular characteristic (e.g. Bb, bb)

Question 38

What does phenotype mean?

Answer 38

It describes the physical appearance of an individual regarding a particular characteristic (e.g. black or brown fur in a mouse)

Question 39

What are the sex chromosomes in females and males?

Answer 39

Female= XX Male= XY

Question 40

Every pregnancy has a —/— chance of it being a boy, or girl.

Answer 40

50/50 chance

Question 41

What occurs when you have polydactyly?

Answer 41

You get extra fingers and/or toes.

Question 42

Is polydactyly caused by a dominant or recessive allele?

Answer 42

Dominant

Question 43

What does cystic fibrosis cause?

Answer 43

It causes your cell membranes to prevent the movement of certain substances and means the mucus made in areas of the body becomes very thick. Your lungs stop working properly because they get clogged up. The pancreas can’t secrete enzymes properly because they’re clogged. You become infertile.

Question 44

How does cystic fibrosis affect the body?

Answer 44

It affects many organs of the body, especially the lungs, the digestive system and the reproductive system.

Question 45

How is cystic fibrosis treated?

Answer 45

Physiotherapy and antibiotics to keep the lungs clear of mucus. Enzymes replace the ones the pancreas can’t produce. THERE IS NO CURE!

Question 46

Is cystic fibrosis caused by a recessive or dominant allele?

Answer 46

Recessive

Question 47

What makes someone a carrier of cystic fibrosis?

Answer 47

They have the allele but don’t suffer from the condition.

Question 48

Is there currently a way to cure genetic disorders?

Answer 48

Nope

Question 49

When is aminocentesis carried out?

Answer 49

At around 15-16 weeks of pregnancy

Question 50

What does aminocentesis involve?

Answer 50

Taking some of the fluids from around the fetus, it contains fetal cells which can be used for genetic screening

Question 51

When does chorionic villus happen?

Answer 51

Between 10-12 weeks of pregnancy

Question 52

What does chorionic villus involve?

Answer 52

Taking a small sample of tissue from the developing placenta, to provide fetal cells to screen

Question 53

What risks are there from chorionic villus and aminocentesis?

Answer 53

Miscarriage

Question 54

What happens during genetic screening after you have the cells?

Answer 54

The DNA is isolated from the embryo cells and tested for specific disorders.

Question 55

What are problems with embryo screening?

Answer 55

- risk of miscarriage -false positives and negatives -expensive