Topic B3

Question 1

Monohybrid inheritance

Answer 1

Inheritance of a single characteristic

Question 2

How many chromosomes do human body cells have?

Answer 2

23

Question 3

Which chromosome pair determines the sex?

Answer 3

23rd

Question 4

Female gametes

Answer 4

XX

Question 5

Male gametes

Answer 5

XY

Question 6

Family pedigree

Answer 6

-Show how genetic disorders are inherited
-horizontal lines link parents
-vertical lines connect parents to children

Question 7

Variation

Answer 7

Differences in characteristics of organisms

Question 8

Mutation

Answer 8

-Random change to order of bases in DNA (order determines what protein is made)
-not all mutations affect phenotypes

Question 9

Genetic variation

Answer 9

Differences in the genes individuals inherit

Question 10

Environmental variation

Answer 10

Variation due to conditions organism developed in- acquired characteristics e.g leaf colour

Question 11

The Human Genome Project

Answer 11

-complete human genome worked out
-genes linked to diseases can be identified

Question 12

What does the human genome project help with?

Answer 12

-prediction and prevention
-treatment and genetic disorders
-developing medicines

Question 13

DNA

Answer 13

Polymer made up of 2 strands coiled into a double helix

Question 14

Parts of a DNA strand

Answer 14

-phosphate
-nucleotide (repeating, make up DNA polymer)
-sugar
-bases

Question 15

Base pairs held together by weak hydrogen bonds

Answer 15

AT
CG

Question 16

Stages of sexual reproduction

Answer 16

1. Parents produce haploid gametes (sex cells)
2. Gametes combine during sex
3. Diploid zygote (fertilised egg) is produced, contains csomes from both parents

Question 17

Chromosomes

Answer 17

Long molecules of DNA that normally come in pairs

Question 18

Haploid

Answer 18

Containing 1 copy of csome 

Question 19

Diploid

Answer 19

Containing two copies of each chromosome, normal cells

Question 20

Meiosis

Answer 20

Cell division that produces four haploid daughter cells

Question 21

Stages of meiosis

Answer 21

-DNA copied
-Division 1, 1 copy of each chromosome produced
-Division 2, 4 haploid gametes produced

Question 22

Stages of extracting DNA from fruit

Answer 22

1. Mash fruit+detergent (breaks down cell membranes to release DNA)+salt (makes DNA stick together)
2. Mix well
3. Filter the mixture+ice cold alcohol
4. DNA appears as a white stringy precipitate. Fish out with glass rod

Question 23

Genome

Answer 23

All of an organism’s DNA

Question 24

Gene 

Answer 24

A small section of DNA 

Question 25

Allele

Answer 25

A version of a gene

Question 26

Dominant

Answer 26

An allele that is always expressed (used to make protein)

Question 27

Recessive

Answer 27

An allele that is only expressed when 2 copies are present

Question 28

HomozygouS

Answer 28

Alleles for a trait are the same

Question 29

HeTerozygous

Answer 29

An organisms alleles for a trait are different

Question 30

Genotype

Answer 30

An organisms combination of alleles

Question 31

Phenotype

Answer 31

The characteristics an organism has