Year 10 Biology Revision

Nucleotide

The basic structural unit of DNA, consisting of a deoxyribose sugar, a phosphate and a nitrogen base.

Gene

The factor that determines an inherited characteristic, located in the chromosomes

A protein code for a feature

Allele

A variation of a gene.

Chromatin

Highly coiled DNA molecule

Protein

An organic compound made of amino acids that controls chemical reactions in the body.

Helicase

Enzyme responsible for separating the two sides of the DNA molecule

DNA Polymerase

Enzyme involved in attaching loose nucleotides to the exposed DNA strand

DNA Ligase

Enzyme involved in reattaching the bonds that hold the nucleotides together to form DNA

Cell Wall

Provides structure, support and protection for the cell

Cell Membrane

Regulates the transport of materials entering and exiting the cell

Chloroplast

Produces energy through photosynthesis and to store food away

Mitochondria

Generates the chemical energy needed to power the cell

Vacuole

To store food waste and water. Sequesters (Cust of)f waste products.

Nucleus

Controls the genetic information and characteristics of an organsim

Cytoplasm

Holds the components and protects them from damage in a cell.

Incomplete Dominance

A form of inheritance in which one allele for a specific trait is not completely dominant over the other allele

Co-Dominance

A form of inheritance in which both alleles for a specific trait present equally in the phenotype

Genotype

The combination of alleles to make up the phenotype. The genes that are present in an individual, usually represented by letters: RR, Rr, rr

Phenotype

The physical appearance of an individual as determined by the genotype

eg) Red hair

Mendelian Inheritance

Natural Selection

The process by which a species becomes better adapted to its environment

Artificial Selection

An evolutionary process in which humans consciously select for/against particular features in an organism

Sexual Selection

The process by which individuals select mates on the basis of heritable traits

Selection Pressure

The pressure exerted by environmental factors in causing the death of organisms with characteristics not suited to the environment.

Eg:

- Predators

- Harsh environment

- Weather

Pressure --> Selection --> Survival advantage --> Reproduce --> Pass on alleles to offspring

Mutation

A new variation, caused by the permanent change in a gene or chromosome

Transmutation

The evolutionary conversion of one species to another

Favourable Trait

Traits that are suited to the environment and favour the reproductive success of an individual

Population

- Has variations

A group of organisms of one species that interbreed and live in the same place at the same time.

Gene Pool

The combination of all the genes (including alleles) present in a reproducing population or species

All available genes and their frequency

Species

A group of organisms that can reproduce with one another and create viable, fertile offspring

Evolution

A process of gradual change that takes place over many different generations

Adaptation

Any change in an organism that improves its chance of survival

Types:

STRUCTURAL

BEHAVIOURAL

PHYSIOLOGICAL

Structural (functional) Adaptation

Adaptations in the design/build of the creature

Eg) Shark teeth backwards and shredding

Behavioural Adaptation

Changes in behaviour that gives a better chance of survival

Eg) Hunting in packs, co-operative hunting

Physiological Adaptation

A chemical body process that improves your chance of survival

Eg) Making spider silk

Extinction

The termination/dying out of a species

Darwin's 4 postulates

- Individuals within a species show variation

- More offspring are produced than survive

- Offspring that do survive have heritable traits (must be able to reproduce and pass on)

- There is a struggle for existence within populations (they grow and change)

Those with desirable variation survive and produce more

EXAMPLE:

Accidental Genetic Drift

Change of allele frequencies due to random changes. One of the five forces that can cause evolutionary change.

- Responsible for random changes in a gene pool

There are two types:

- The founder effect

- The Bottleneck effect

The Founder Effect

One form of genetic drift. It describes the decrease in genetic variability that happens when a small sample of individuals separates from a larger population

RANDOM CHANGE IN ALLELE VARIATION

The Bottleneck Effect

Starts with a large population, then through a catastrophic event many individuals are wiped out decreasing the population and genetic variability.

Whatever survives makes a smaller population.

RANDOM CHANGE IN ALLELE VARIATION

Speciation

The formation of a new species due to evolution. They are unable to breed and create fertile offspring with the original population

> Occurs when a group within a species separates from other members and develops its own unique characteristic

Environmental Resistance

> Limits the growth of the population as the population fills up the environment

(Lack of food, change in temp, diseases)

Population size that is limited by Density Independent Factors

- May effect all individuals in a population equally

PHYSICAL FACTORS:

> Rainfall

> Acidity

> Temperature

> Humidity

> Salinity

CATASTROPHIC EVENTS

> Fire > Tsunami

> Flood > Earthquake

> Volcanic eruption > Drought

Population size that is limited by Density Dependent Factors

- Have greater effect when population density is higher

Things that are influenced by the density of the population:

> Food supply

> Disease

> Parasites

> Competition

> Predators

The Class System

Dumb Kings Play Chess On Flimsy Glass Squares

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Human Classes

Domain = Eukaryote

Kingdom = Animals

Phylum = Chordate

Class = Mammal

Order = Primates

Family = Hominidae

Genus = Homo

Species = Sapiens Sapiens

Characteristics of Eucayota

- Multicellular

- Nucleus (DNA)

- Organelles: Cytoplasm, Ribosomes, Peroxisomes, Vacuoles, Mitochondria, Golgi apparatus, Endoplasmic reticulum, Centrosome, etc.

Characteristics of Procaryota

- Unicellular

- No Nucleus (Unorginised DNA)

- No Organelles

The 3 Characteristics of Chordates

1) A Notochord

2) Neural tube

3) Pharyngeal slits/pharyngeal pouches (Gills)

The 7 Characteristics of a Sub Phylum - Vertebrates

1) A bone structure and a backbone -> Vertebra (Spine)

2)A Ventral heart

3) 4 Appendages (arms and legs)

4) Red Blood that circulates through vessels - Hemoglobin and O2

5) An advanced nervous system

6) Bilateral symmetry

7) Tail at some stage (humans have tailbone)

The 2 Characteristics of Mammalia:

1) Have fur or hair covering the body

2) Produces milk/mammary glands

Characteristics of Primates (13 but need to know 6 right now 😃)

1) Large brained

2) Forward facing eyes (2)

3) Colour vision Stereoscopic/Binocular vision

4) Pentadactyl digits (5)

5) Dermal ridge -> Fingerprints

6) Opposability

Classifications for animals: MRS GREN

Movement - Important for organisms to catch food and avoid predators

Respiration - Process of all living things to convert energy that can be used by cells

Sensitivity - How animals respond to their environment e.g. changes

Growth -

Reproduce - Either asexual or sexual.

Excretion

Nutrition

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