Biology EOCT Review

Milton High School

Cell Organelles

• Nucleus – holds DNA• Cell membrane – what comes in and goes out• Mitochondria – powerhouse of the cell• Ribosomes – protein synthesis• Lysosomes – digestion• Cell wall – structural support (ex. plants)• Vacuoles – storage• Chloroplasts – in plants for photosynthesis

Animal cell vs. Plant cell

Differences in Cells

Prokaryote• Lacks nucleus• No membrane-bound

organelles• Has a cell wall• Has a cell membrane• Bacteria

Eukaryote• Has a nucleus• Has membrane-bound

organelles• Found in plants, animals,

fungi, and protists

Viruses• Relies on a host cell to reproduce• Has DNA or RNA

Osmosis• How water diffuses into a cell• Diffusion is process which molecules of a substance move

from an area of high concentration to an area of low concentration

Macromolecules

• Carbohydrates – glucose and sucrose– Provide quick energy– Polysaccharides are largest

• Lipids – fats, oils, waxes– Insoluble in water– Storage of energy

• Proteins – basic building materials– Also contain nitrogen– Made of amino acids (there are 20)

Photosynthesis

Mitosis vs. Meiosis

Mitosis• Generates TWO identical

cells• Maintains chromosome

number (Diploid number)• Occurs in body cells

(somatic cells)

Meiosis• FOUR cells are formed • Each with half of the

number of chromosomes (Haploid number)

• Forms sex cells (gametes)• Requires two cell divisions

Genetics

• Genes are located on chromosomes• Homozygous – both alleles are the same (TT)• Heterozygous – alleles are different (Tt)• Dominant alleles express themselves• Recessive alleles are hidden• Phenotype – physical appearance• Genotype – set of alleles individual receives

Some important ecology terms

• Community – multiple populations• Abiotic – non-living items in environment• Trophic levels – different levels in food chain– Each level gets energy from level below it– Less energy available as move up to next level

• Habitat – where an organism lives• Niche – what an organism does in habitat

Less energy available to next level – some

energy used for respiration, growth,

reproduction.

Parasitism – one species benefits and the other species can be

harmed (need a host)

Tick is an example

Commensalism – one species benefits and the other species is

neither harmed nor helpedThe remora and the shark

is an example – the remora is a fish which has

“suction” disks which allow it to attach to shark

without hurting the shark

Mutualism – both species benefit

A lichen is formed by a relationship between a fungus and a green algae. The fungus

anchors the lichen and protects the algae from direct sunlight

and extreme temperature fluctuations. The green algae

performs photosynthesis, providing food for itself and the

fungus.

Natural selection - results in the evolution of organisms best adapted to the

environment

Nectar feeding

Seed-eating

Acid rain – produced when nitrogen oxide (from car exhaust) or sulfur dioxide (from burning fossil fuels) mixes with rain

Enhanced greenhouse effect – more heat trapped –caused by excess carbon dioxide and other greenhouse gases

released into the atmosphere