CB3 - Genetics

Question 1

What organisms can produce asexually?

Answer 1

Most insects
Many plants

Question 2

What does asexual reproduction produce?

Answer 2

Genetically identical ‘clones’ offspring of the parent.

Question 3

What are the advantages of sexual reproduction?

Answer 3

Creates variation, so there is a greater chance that offspring will be suited to new conditions.

Question 4

What are the advantages of asexual reproduction?

Answer 4

Quicker

Question 5

What are gametes?

Answer 5

Sex cells -
egg
sperm

Question 6

What is formed when two gametes fuse during fertilisation?

Answer 6

Zygote

Question 7

What does the zygote form?

Answer 7

A ball of cells using mitosis.

Question 8

Where are the genetic instructions for an organism found?

Answer 8

DNA

Question 9

What is a genome?

Answer 9

The entire genetic material of an organism.

Question 10

What is the Human Genome Project?

Answer 10

A project dedicated to determining the base pairs that make up human DNA

Question 11

What are genes?

Answer 11

Sections of DNA that contain a code for making protein.

Question 12

How many ‘different’ chromosomes are there in a human body cell?

Answer 12

23

Question 13

Is a human body cell diploid or haploid and why?

Answer 13

Diploid
Contains two sets of 23 unique chromosomes.

Question 14

What is meiosis?

Answer 14

A type of cell division that results in the production of four haploid daughter cells.

Question 15

What happens to a cell during meiosis?

Answer 15

The chromosomes replicate and their copies stay stuck to one another. There are now 4x 46 chromosomes.
The cells divide into two and then two again.
This leaves four haploid cells.

Question 16

What is the structure of DNA?

Answer 16

Nucleus contains chromosomes.
A chromosome contains one long DNA molecule.
That DNA molecule is tightly coiled in proteins.
DNA is a double helix and polymer.

Question 17

What are the four bases in DNA?

Answer 17

Adenine
Thymine
Cytosine
Guanine

Question 18

Which bases form complementary base pairs?

Answer 18

A and T
C and G

Question 19

What are the bases attached to?

Answer 19

A sugar attached to a phosphate group.

Question 20

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

Answer 20

Nucleotide

Question 21

How are the bases held together?

Answer 21

The negatively charged part of one base attracts the positively charged part of another base, this forms hydrogen bonds.

Question 22

Is DNA unique?

Answer 22

Yes, except for identical twins.

Question 23

What is the experiment to extract DNA?

Answer 23

Mash the fruit to break down the cell wall
Mix together water, salt and washing-up liquid.
This breaks down the surface membrane and the membrane around the nucleus.
Filter the mixture and collect the filtrate.
Add protease to the filtrate to break down the proteins coiled around the DNA.
Add ethanol which forms a precipitate.

Question 24

What are alleles?

Answer 24

Different forms of the same gene.

Question 25

What is it called if both alleles for one gene are the same?

Answer 25

Homozygous

Question 26

What is it called if the alleles for one gene are different?

Answer 26

Heterozygous

Question 27

What is a recessive allele?

Answer 27

For that characteristic to be seen both alleles have to be ressisive.

Question 28

What is a dominant allele?

Answer 28

For that characteristic to be seen one allele has to be dominant.

Question 29

What is a genotype?

Answer 29

The alleles in an organism.

Question 30

What is a phenotype?

Answer 30

What observable characteristics an organism has.

Question 31

What are the male sex chromosomes?

Answer 31

XY

Question 32

What are the female sex chromosomes?

Answer 32

XX

Question 33

What are Punnett squares?

Answer 33

A way to demonstrate inheritance and work out the probability of offspring inheriting certain genotypes.

Question 34

How do we show dominant and recessive genes?

Answer 34

Capital letter for dominant Lower case letter for recessive

Question 35

What are mutations?

Answer 35

A change in a gene that creates a new allele. Errors in the genetic sequence

Question 36

What is genetic variation?

Answer 36

Variation caused by the different alleles inherited during sexual reproduction. Variation caused by mutations affecting the phenotype.

Question 37

What is environmental variation?

Answer 37

Variation caused by surroundings. E.g. - Plants height based off light and water.

Question 38

What are acquired characteristics?

Answer 38

Characteristics that are changed by the environment during the life of an individual.

Question 39

What is discontinuous variation?

Answer 39

Where data can only take a limited set of values.

Question 40

What is continuous variation?

Answer 40

Where data can be any value in a range.

Question 41

What are the three types of mutations?

Answer 41

Deletion Insertion Substitution

Question 42

What is a deletion mutation?

Answer 42

When one base in the genetic sequence is deleted

Question 43

What is a insertion mutation?

Answer 43

When one base is added to the genetic sequence

Question 44

What is a substitution insertion?

Answer 44

When one of the bases in a genetic sequence changes

Question 45

What is sickle cell mutation?

Answer 45

A mutation that changes the shape of the blood cell

Question 46

What is cystic fibrosis?

Answer 46

A mutation that causes cysts to form in the lungs