Genetics and Variation - Half Term 1 (9Aa, 9Ab, 9Ac)

Question 1

What is environmental variation?

Answer 1

Variation caused by an organism’s surroundings, including abiotic factors (e.g. temperature, light) and biotic factors (e.g. competition, predators)

Examples:
- piercings, clothing, weight

Question 2

What is genetic variation? (Also known as inherited variation)

Answer 2

Variation caused by an organism’s genes, passed down from the parents

Examples:
- hair colour
- eye shape
- blood group

Question 3

What is a species?

Answer 3

A group of living organisms that can interbreed and produce fertile young/offspring

Question 4

The surroundings of an organism are called its _______________

Answer 4

Environment

Question 5

What are characteristics?

Answer 5

Distinctive biological traits or features of the organism

Question 6

What is the difference between an environmental factor and a physical environmental factor?

Answer 6

An environmental factor can be abiotic or biotic, but a physical environmental factor can only be abiotic

Question 7

What is a resource?

Answer 7

A substance or object in the environment required by an organism for normal growth, maintenance and reproduction

Question 8

What is the environment?

Answer 8

All living and non-living elements by which an organism is surrounded

Question 9

What is an abiotic factor?

Answer 9

Non-living part of an ecosystem that shapes its environment

Question 10

What is a biotic factor?

Answer 10

A living organism that shapes its environment

Question 11

What is continuous variation?

Answer 11

A characteristic that changes gradually over a range of values (e.g. height)

Question 12

What is discontinuous variation?

Answer 12

A characteristic that comes in groups rather than a range (e.g. blood group)

Question 13

What is classification?

Answer 13

The process of arranging organisms into groups based on similar characteristics

Question 14

How should discontinuous variation be shown in a graph?

Answer 14

• bar chart
• spaces in between the bars
• no ‘normal distribution’ curve
• group along x axis

Question 15

How should continuous variation be shown in a graph?

Answer 15

• histogram
• no spaces in between the bars
• a ‘normal distribution curve’

Question 16

What is a gamete?

Answer 16

It is a sex cell - sperm for males and eggs for females

Question 17

How many chromosomes does an egg cell have?

Answer 17

23

Question 18

How many chromosomes does a sperm cell have?

Answer 18

23

Question 19

How many chromosomes does a zygote have?

Answer 19

46 in 23 pairs

Question 20

How many chromosomes does an embryo have?

Answer 20

46 in 23 pairs

Question 21

What does DNA stand for?

Answer 21

Deoxyribose Nucleic Acid

Question 22

What shape does DNA take?

Answer 22

Coiled double helix (like a twisted ladder)

Question 23

___________ come as identical homologous pairs (except sex chromosomes)

Answer 23

Chromosomes

Question 24

How many pairs of chormosomes are there in humans

Answer 24

23, 46 total

Question 25

What are genes?

Answer 25

Genes are sections of DNA/chromosomes, and they code for a specific characteristic. They are inherited from our parents and can come in different forms known as alleles

Question 26

What is an allele?

Answer 26

Genes in different forms

Question 27

A long strand of DNA is made up of combinations of ___ bases

Answer 27

4

Question 28

What are the pairings of the bases in DNA?

(hint: AGTC)

Answer 28

Adenine - Thymine
Cytosine - Guanine

Question 29

Where are chromosomes found?

Answer 29

Nucleus of a cell

Question 30

True or False: One of each pair of choromosomes comes from each parent

Answer 30

True

Question 31

There are different versions of each gene, one is often ________ over the others

Answer 31

Dominant

Question 32

DNA is a _________ made from _________ joined together

Answer 32

monomer
polymers

Question 33

DNA is a long chain (a)___________ that is made up of a combination of (b)____ DNA bases

Answer 33

a. molecule
b. four

Question 34

What is the phosphate ion bonded to in a DNA molecule

Answer 34

Sugar

Question 35

What is the sugar bonded to in a DNA molecule?

Answer 35

Base

Question 36

What are the repeated units (monomers) of a DNA molecule named?

Answer 36

Nucleotides

Question 37

What are the three components of a nucleotide?

Answer 37

1. sugar
2. phosphate group
3. base (ATGC)

Question 38

What is the name of the base beggining with A?

Answer 38

Adenine

Question 39

What is the name of the base begining with T?

Answer 39

Thymine

Question 40

What is the name of the base begginning with C?

Answer 40

CytosineW

Question 41

What is the name of the base beginning with G?

Answer 41

Guanine

Question 42

Draw a diagram of a nucleotide

Answer 42

(P)\
\
⬠Sugar (Deoxyribose) —- |Base|

Question 43

What is a homozygous allele?

Answer 43

One in which the alleles are the same (e.g. aa, BB)

Question 44

What is a heterozygous allele?

Answer 44

One in which the alleles are different (e.g. Aa, Bb)

Question 45

Dominant alleles are shown using (capital/lowercase) letters

Answer 45

Capital (e.g. B for brown eyes)

Question 46

Recessive alleles are shown using (capital/lowercase) letters

Answer 46

Lowercase (e.g. b for blue yees)

Question 47

What is a genotype?

Answer 47

The genetic makeup of an organism (e.g. aa, Bb, CC)

Question 48

What is a phenotype?

Answer 48

The physical expression or outcome of an allele pair (e.g. blue eyes)

Question 49

What type of genotype is BB?

Answer 49

Homozygous dominant

Question 50

What type of genotype is bb?

Answer 50

Homozygous recessive

Question 51

What type of genotype is Bb?

Answer 51

Heterozygous

Question 52

What joins the base to the sugar?

Answer 52

Nitrogen atom

Question 53

What types of bonds are there between the nucelotides?

Answer 53

Covalent

Question 54

How are the two nucelotide chains held together?

Answer 54

Hydrogen bonds