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 helped The 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