Genetics

Nucleotide/base pairings

Adenine and thymine, cytosine and guanine

Relationship between DNA, genes and chromosomes

DNA are genetic material in a double helix shape. Genes are segments of DNA to make traits. Chromosomes are long strands of DNA.

Substitution

A DNA mutation where a different base is incorrectly inserted

Insertion

A DNA mutation where one or more extra bases are inserted by mistake

Deletion

A DNA mutation where one or more bases are removed

Deoxyribonucleic acid

A long molecule found in the nucleus of cells that carries the genetic information of an organism

Genes

A specific segment of DNA that codes for a characteristic

Chromosome

A tightly coiled strand of DNA found in the nucleus of the cell. 46 are in somatic cells, 23 are found in gametes.

Haploid

A cell with one set of chromosomes, e.g sperm and egg cells

Diploid

A cell with 2 sets of chromosomes, e.g somatic cells

Karyotype

A picture of an organism's full set of chromosomes

Down syndrome

An extra copy of chromosome 21

Monosomy

One chromsome of a pair missing

Trisomy

An extra copy of a chromosome is added to a pair

Translocation

When a part of a chromosome breaks and reattches to another chromosome

Difference between mitosis and meiosis

Mitosis produces 2 identical diploids from the parent cell. Meiosis produces 4 haploids with half as many chromosomes.

How does meiosis contribute towards genetic variation?

Genetic information is exchanged by both pairs of chromosomes during the Prophase of meiosis

Genotype

The genetic code of an organism for a specific trait

Phenotype

The physical expression of a genotype

Allele

A variation of a gene

Homozygous

When there are 2 identical alleles present

Heterozygous

When there are 2 different alleles present

Helicase

An enzyme which breaks down the hydrogen bonds of bases and unzips the DNA

Primase

An enzyme that attatches primers to a DNA strand and preps it for replication

Polymerase

An enzyme that connects to the primer and creates new bases of DNA

Exonuclease

An enzyme that removes all the RNA primers from both strands of DNA

Ligase

An enzyme that seals up fragments of DNA in both strands

RNA

Carries genetic instructions from DNA

Primers

Small pieces of RNA that attatches to bases to prep for replication

Process of DNA replication

DNA is unzipped by helicase -Primase preps for replication - Polymerase connects new bases one at a time - Exonuclease removes RNA and more polymerase replaces it with DNA - Ligase seals up DNA strands

Biotechnology

The use of living organisms to develop products

In vitro fertiliasation (IVF)

Fertilisation of the sperm and egg that occurs outside the human body

Stem Cell

A cell type that is unspecialised and can develop into other types of cells

Adult stem cell

Limited in their dividing and what kind of cell it can develop to

Embryonic stem cell

Can develop into almost any cell

Types of biotechnology

Stem cell, IVF, genetically modified crops

Advantage of stem cell biotechnology

Can cure many diseases and disorders, e.g diabetes and Parkinson’s disease

Disadvantage of stem cell biotechnology

Stem cell science is still new so it is only used to its full extent in bone marrow transplants

Social consideration of stem cell biotechnology

Stem cell science is still new so the long-term impacts on people are unknown

Ethical consideration of stem cell biotechnology

Harvesting embryonic stem cells kills off pre-embryo cells, which can deter people who believe life starts at conception

Advantage of IVF

It allows people to have children naturally despite age, health or other factors

Disadvantage of IVF

It is extremely expensive for each treatment and is invasive to the mother

Social consideration of IVF

It is not easily accessible to the public due to the costs

Ethical consideration of IVF

Past reports show that doctors have inserted multiple fertilised eggs into a woman, instead of one, to boost high success rate statistics. This is dangerous to the babies and the mother.

Advantages of genetically modified crops

Can contain more nutrients, less space needed to grow, use less water, pesticides, soil and fertilisers, more resistant to herbicides

Disadvantages of genetically modified crops

Pollen from GM crops may carry over to other crops and cross-polinate, resulting in different plants grown.

Social consideration of genetically modified crops

GM crops can contaminate neighbouring farms, leading to other farmers not being able to label their crops as ‘certified organic’ and leading to less income.

Eithical consideration of genetically modified crops

More foods are genetically modified but aren’t labelled as so, leading to consumers having less options on choosing what they want.