Yr 11 Biology Exam Revision

Polygenic inheritance

Characteristics controlled by many genes, creating more variation

Monomorphic inheritance

controlled by one gene, less variation

Inherited Variations

Variation that has been genticaly inherited and are passed on and cannot be naturally changed

Aquired Variation

Traits from an individual's environment can be changed.

Continuous variation

Controlled by many genes, lots of subtle variation, line curve

Silent Mutations

When a base is changed but the protien remains the same

Nonsense Mutation

An early stop codon is employed due to base changes.

Translocation

When sections or entire chromosomes are swapped with homologous or different chromosomes.

Locus

The location of a gene (the house that the gene lives in)

Monohybrid Cross

Only one gamete is inherited per parent

Dihybrid cross

When two gametes are inherited per parent.

Gene Pool

A complete set of unique alleles in a species can be large or small.

What is Missense mutations

When there are changes to the amino acid originally meant to be coded, resulting in the protein may not working.

Induced Mutations

Chemicals and radiation, including both ionised and non-ionised radiation.

Spontaneous mutation

Errors in DNA replication or recombination

Autosomal Dominant Inheritance

Shown in every generation as the traits are dominant over recssive ones.

Autosomal Recessive Inheritance

Recessive phenotypes only visible in homozygous recessive individuals, a dominat gene will mask the trait and seems to skip a generation.

What would be the chances of a father giving the trait to his daughters and sons if he has a dominant X-linked disease?

100% to daughters, 0 to sons.

what is a Y-linked gene and what does it affect?

Where the Y chromosome holds the trait. It only goes from father to son and affects testicle and sperm production, hairy ears, numerous male-specific proteins.

Frame Shift Mutation

When a mutation either inserts or deletes a series of nucleotides.

Complete Dominance

Discontinuous Variation

by one gene, set number of phenotypic displays, bar graphs

Phototropism

Reaction to light

Geotropism

Reaction to gravity

Thigmotropism

Reaction to touch

Pyrimidines (pyramid)

1 carbon ring, includes C and T

Purines (glasses)

2 carbon rings, includes A and G

Anti-parrellel

5’ on top of lagging phosphate group

Chromatin

Mix of proteins and nucleuic acids

Chromosomes

Condensed chromatin during DNA replication

Nucleosome

“Beads” of protein and DNA that make up chromosomes

Histones

The protien that DNA is wrapped around to form nucleosomes

Karyotype

Number of chromosomes

Stuctrual Genes

Required to make a protein

Regulatory Gene

If structural genes are on or off

Stages of translation

T - translation

I - initiation

E - elongation

T - termination

What happens in initiation?

mRNA enters the cytosol, ribosome forms around start codon

What happens in Elongation?

tRNA brings amino acids to mRNA and the polypeptide is formed

What happens in Termination?

Protein release factor recognises stop codon and polypetide is released

The central dogma of molecular biology

DNA - RNA - Protein or RNA - Protein

Characteristics of DNA

Double-stranded, thymine, can’t leave the nucleus

Charactristics of RNA

Single-stranded uracil, can leave the nucleus

tRNA

The reader of the mRNA, matches amino acids to code

mRNA

Messenger

rRNA

The physical frame

Homologous Chromosomes

Same height, loci, alleles, centromere

Germline chromosomes

X and Y

Autosomal Chromsomes

Any non-sex chromosome

Non disjunction

Failure to split chromosomes

Down Syndrome

Trisome 21

Turner Syndrome

One X

Klienfelter Syndrome

Additional X

Independant Assortment

Random assortment of genes

Ploidy

Set number of chromosomes in a cell

Haploid

n, one set of chromosomes

Dihaploid

2n, 2 sets of chromosomes

Gene

Section of DNA coding for a protien

Monohybrid Cross

One allele is inherited per parent (Aa)

Dihybrid Cross

Two alleles are inherited per parent (AaBB)

P

Parental Generation

F1

First filial generation

F2

Second filial generation

Test cross

Find out what an unknown genotype is

Complete Dominance

Only one gene shown

Incomplete Dominance

Blended genotype (red x white = pink)

Codominance

Both expressed (red x white = spotty)

Inherited Traits

Cannot be changed, not altered by environment

Aquired traits

Can be changed

Gene pool

Complete set of possible genotypes in a species

Binary Fission

Single celled organism splits into two (exponential)

Budding

Development of an organism from the outgrowth of the parental organism

Spore Formati

Tough capsules formed by cell division

Fragmentation

When an organism breaks in half and can re-grow missing parts

Pathernogenisis

When unfertilised eggs can develop in mature individuals

Horizontal gene transfer

Improves genetic diversity by sharing DNA

Vegetative propagation

The cutting and planting of different plants

Human Gametes

Ova and sperm

Plant Gametes

Pollen and Ova

Structural Adapation

Visible, inherited trait

Behavioural Adaptation

Innate, or learned behaviours

Physiological Adaptations

Internal process to optimise health and reproduction

Parastism

One benefit, one is negatively affected

Mutualism

Mutually beneficial

Commensalism

One benefits, one uneffected

Amensalism

One uneffected, one killed or harmed

Pathogen

Agent that causes disease

Consequensalism

Judges right from wrong based on consequences

Example of consequensalism

Lying is ok if it is done to protect someone

Deontology (Deon)

What the absolute rule is

Deontology example

Truth is always right

Arlaic virtues

Moral character of the person carrying out the actions

Example of Arelaic virtues

A customer returning to a store after accidentally not scanning something

Bioethical Concepts

N - non-maleficence
I - integrity
R - respect
B - beneficence
J - justice

Genome vs proteome

The genome is the complete set of DNA (including all genes) in an organism, while the proteome is the entire set of proteins expressed by a cell

Hemizygous (half)

Only one copy of a gene or chromosome instead of 2

Mendel’s laws of Inheritance

Law of Dominance and Uniformity

Law of Segregation

Law of Inpendant Assortment

Kinetochore

Structure that assembles the centromere during replication