Section 3 & 4

Question 1

Meiosis

Answer 1

Same as mitosis but divide again
Cell division for reproduction in sex organs
Haploid – non-identical

Question 2

Sexual reproduction

Answer 2

Where genetic information from two organisms combine to produce offspring which are genetically different
Sperm (gamete) + egg( gamete) = zygote

Question 3

DNA structure

Answer 3

It’s in a double helix shape
Held together by week hydrogen bonds
It’s a polymer made up of four different types of bases in each repeating unit

Question 4

DNA

Answer 4

DNA is Stored as chromosomes and contains genes

Wilkins and Franklin got x-ray out of DNA
Watson and Crick made model

Question 5

Gene

Answer 5

Gene is a section of DNA on a chromosome codes for a particular protein

Question 6

Chromosome

Answer 6

Chromosomes are long coiled up molecules of DNA

Question 7

Genotype, phenotype, homozygous , heterozygous

Answer 7

Genotype – the genes the person possesses
Phenotype – physical trait person shows
Homozygous – same
Heterozygous – different

Question 8

Genetic diagrams

Answer 8

Characteristics are caused by genes
Dominant allele is displayed
Alleles represented by letters, dominant – capital, recessive – lower
Different versions of genes are called alleles

Question 9

Variation

Answer 9

Continuous – height, weight
Discontinuous – gender, eyecolour
Genetic and environmental factors cause variation – climate, diets, accidents, culture

Question 10

Human genome project

Answer 10

Thousands of scientists collaborated to find every single human gene and to sequence bases to work out where on each chromosome The genes for different characteristics were
To help predict and prevent diseases – early treatment - tailor made medicine
Test and treat for inherited diseases
Get new/better medicines – highlights common genetic variations, design new drugs, more effective

Question 11

Natural selection stages

Answer 11

Variation
Competition
Better adapted
Pass on genes
New species
(V,C,BA,POG,GOT)

Question 12

Natural selection

Answer 12

Process where organisms better adapted to their environment survive and produce offspring – Charles Darwin
Individuals in a population should fit in variation because of difference in alleles – new Alleles arise through mutations

Question 13

Evidence for evolution

Answer 13

Bacteria – develops random mutations in DNA, create new alleles, change in Characteristics (may become resistant to antibiotics)
fossils – lower in the ground the older it is, the complexity (dating fossils) carbon dating
Lucy – 3.4 million years old, leaky found it
Ardi – 4.4 million years old, 1 million year gap
Incomplete fossils

Question 14

Evolution

Answer 14

Process by which different types of living organisms are believed to have developed from earlier forms

Question 15

Fossil evidence for human evolution

Answer 15

Homo habilis, Homo sapiens, homo neanderthalensis, homo erectus
Trends - tools became more complex, bigger Skull due to bigger brain (more intelligent)

Question 16

Classification

Answer 16

The arrangement of animals and plants in taxonomic groups according to their similarities
Domain, kingdom, Phylum, class, order, family, genus, species
Three domains – bacteria, archaea, eukarya

Question 17

Five kingdoms

Answer 17

Animalia- multi-cellular 
Plantae- multi-cellular
Fungi – multi-cellular
Protoctista- uni-cellular nucleus
Prokaryotae- uni-cellular no nucleus

Question 18

Genetic engineering

Answer 18

1 cut out desired gene with restriction enzyme
2 courtsopen plasmid with same restriction enzyme to get complimentary sticky ends
3 stick Gene into plasmid using ligase enzyme
4. Put plasmid into bacteria
5 bacteria then replicates three mitosis

Question 19

Selective breeding steps

Answer 19

1 Select things to breed
2 breed together (cross pollinate in plants)
3 select offspring with desirable characteristics
4 repeat over generations
Adv- different species
Did adv- reduced genetic variation

Question 20

Selective breeding

Answer 20

Involves choosing parents with particular characteristics to breed together and produce offspring with more desirable characteristics