Inheritance

Question 1

Define genome (of an organism)

Answer 1

the entire genetic material of that organism

Question 2

Define chromosones

Answer 2

The structure made of DNA that codes for all the characteristics of an organism.

Question 3

Define gene

Answer 3

a small section of DNA on a chromosome, that code for a particular sequence of amino acids, to make a specific protein

Question 4

Define DNA

Answer 4

Deoxyribonucleic acid. The material inside the nucleus of cells, carrying the genetic information of a living being.

Question 5

Name some benefits of understanding the human genome

Answer 5

.Helps to understand inherited disorders (caused by genes): able to diagnose and potentially treat these diseases

.Search for genes which are linked to a disease (eg genes that increase the risk of developing cancer or heart disease)

.Helps to understand human evolution and history (understand human migration patterns)

Question 6

What is the order of size between DNA, genome, chromosomes and genes?

Answer 6

small ——————————————- ‘large’
DNA Genes Chromosomes Genome

Question 7

Define nucleotide

Answer 7

a molecule made up of sugar, phosphate and one of four different bases. They are key units in the structure of DNA and RNA

Question 8

Label a picture of a nucleotide

Answer 8

(use image online)
Key features
Sugar Base Phosphate

Question 9

Describe the shape of a DNA molecule

Answer 9

Double helix

Question 10

Explain what is meant by base pairing

Answer 10

a base pair consists of two complementary DNA nucleotide bases that pair together to form a rung of the DNA ladder

Question 11

Name the 4 bases (abbreviations) and what they link with

Answer 11

A – T
G — C

Question 12

Define mitosis

Answer 12

part of the cell cycle where one set of new chromosomes is pulled to each end of the cell forming two identical nuclei during cell division

Question 13

Define cell cycle

Answer 13

the three-stage process of cell division in a body cell that involves mitosis and results in the formation of two identical daughter cells

Question 14

The cell cycle has three stages:
Describe each one

Answer 14

Stage 1: Interphase
.Replication of DNA to form 2 copies of each chromosome and synthesis of new subcellular structures

Stage 2: Mitosis
.Nucleus divides into two
.One set of each chromosome is pulled to each end of the other cell

Stage 3: Cytokinesis
.The cell physically divides into two daughter cells

Question 15

Why is cell division by mitosis so important in the body?

Answer 15

.Growth and repair
.Replace old, worn out cells
.Ensure that each new cell functions like the original (vital for maintaining tissue structure and function)

Question 16

Define meiosis

Answer 16

two stage process of cell division that reduces the chromosome number of daughter cells. It is involved in making gametes for sexual reproduction

Question 17

Define gametes

Answer 17

a reproductive cell that contains only one set of chromosomes (haploid) and is involved in sexual reproduction

Question 18

Name the organs that produce human gametes

Answer 18

Ovaries and Testes

Question 19

Name the male and female human gametes

Answer 19

Male: Sperm
Female: Egg or Ova

Question 20

Describe what happens during meiosis

Answer 20

First, the DNA doubles. Then there are two cell divisions; the daughter cells are haploid and have 23 chromosomes.

Question 21

Define fertilization

Answer 21

the process in which the nucleus of a sperm cell fuses with the nucleus of an egg cell to produce a zygote

Question 22

Define asexual reproduction

Answer 22

the type of reproduction in which a single parent organism, produces offspring without the involvement of gametes or fertilization

Question 23

Define sexual reproduction

Answer 23

the formation of a new organism by combining the genetic material of two organisms

Question 24

Define clone

Answer 24

an organism that’s genetically identical to another organism

Question 25

Why are the offsprings of organisms that reproduce asexually are identical to their parents?

Answer 25

As asexual reproduction only involves one parent, and there's no mixing of genetic material

Question 26

Why are the offsprings of organisms that reproduce sexually are non-identical to their parents?

Answer 26

Due to the mixing of genetic material, during the fusion of gametes. Inheriting a mixture of genes from parents.

Question 27

Advantages of asexual reproduction

Answer 27

.Only one parent is needed; no need to find a mate .Faster than sexual reproduction .Population can increase rapidly when conditions are favourable

Question 28

Advantages of sexual reproduction

Answer 28

.Increases genetic diversity (suited for natural selection) .The species can adapt to new environments due to genetic variation .Disease is less likely to affect ALL the individuals in a population

Question 29

Examples of organisms which produce asexually and sexually

Answer 29

.Malaria parasites .Fungi .Strawberry plant .Daffodils (bulbs)

Question 30

What are the two stages involved in protein synthesis and where do they happen?

Answer 30

Transcription: In the nucleus Translation: In the cytoplasm

Question 31

What happens during transcription in protein synthesis? (Simple)

Answer 31

a copy of a DNA gene is made into a molecule of mRNA (messenger RNA) in the nucleus

Question 32

What happens during translation in protein synthesis? (Simple)

Answer 32

The genetic information encoded in mRNA is used to build a specific polypeptide (protein) chain. Taking place at the ribosomes in the cytoplasm, involves tRNA molecules bringing amino acids to the ribosome based on the mRNA codons

Question 33

Name the four RNA bases (abbreviations) and what they link to

Answer 33

A --- U G --- C

Question 34

Define stem cell

Answer 34

an undifferentiated cell that has the ability to develop into different types of cells, and can also renew itself

Question 35

Define gene expression

Answer 35

the process by which the information encoded in a gene is turned into a function

Question 36

Name some sources of animal stem cells

Answer 36

Embryos Adult tissues (eg bone marrow) Umbilical cord blood

Question 37

Define stem cells in plants

Answer 37

undifferentiated cells located in meristems, the growing regions of plants, that can differentiate into any type of plant cell

Question 38

Define mutation

Answer 38

change in the sequence of DNA of a cell

Question 39

Define allele

Answer 39

version of a gene (eg normal haemoglobin or sickle cell haemoglobin)

Question 40

Define homozygote

Answer 40

Individual has two identical alleles

Question 41

Define heterozygote

Answer 41

Individual has two different alleles

Question 42

Define genotype

Answer 42

genetic makeup of an organism (eg AA, Aa or aa)D

Question 43

Define phenotype

Answer 43

the observable trait of an indiviual

Question 44

Define dominant allele

Answer 44

an allele which will always be expressed in the phenotype

Question 45

Define recessive allele

Answer 45

in only expressed in the phenotype when no dominant alleles are present

Question 46

Define genetic cross

Answer 46

a model used to show all the possible genetic outcomes when you cross together different genes or chromosomes

Question 47

Do a punnett square exam question

Question 48

What are the male and female sex chromosomes?

Answer 48

Male: XY Female: XX

Question 49

Define cystic fibrosis

Answer 49

an inherited disorder that creates a thick sticky mucus, mainly affecting the lungs and pancreas. It is caused by a recessive allele.

Question 50

Define polydactyly

Answer 50

a dominant inherited disorder that results in babies born with extra fingers and/or toes

Question 51

Do a family tree exam question

Question 52

Define genetic screening

Answer 52

screening DNA for inherited disorders; enables the detection of faulty alleles

Question 53

Name some concerns about embryo screening

Answer 53

.Increases risk of a miscarriage .Sometimes give an incorrect result .Means people have to make decisions about whether or not to terminate the pregnancy .Very expensive