Biology Test review

Nucleus

an organelle in a cell that contains most of the cell's DNA, surrounded by phospholipid bilayer (lipids)

cell wall

(plant cells) a semi-rigid structure that lies on the very outside of the cell, has several roles including protecting the cell and providing shape and structure. many materials pass freely through the cell wall.

(plasma) membrane

like another cell wall, made of lipids and controls the movement of materials in and out of the cell. (in both plant and animal cells)

vacuole

Plant cell vacuoles: contain cell sap. sap is a watery solution containing dissolved materials, ions, waste products, and pigments. functions include storage, waste disposal, and growth.

Animal cells: may not always be present

chloroplast

Plant cells: a specialized plastid containing the green pigment chlorophyll. chloroplasts are the site for photosynthesis. photosynthesis uses light energy to convert carbon dioxide into glucose.

Animal cells: chloroplasts and other plastids are not present in animal cells

mitochondrion

mitochondria are the cells energy producers. they use the chemical energy in glucose to make ATP (the cell's usable energy currency)

cytoplasm

a watery solution containing dissolved materials, enzymes, and the cell organelles. (in whole cell)

Covalent and Ionic bonds

join atoms together to produce larger molecules

polarity

arises from unequal distribution of electrons in bonding and affects how molecules interact with each other. this results in slightly negative charged and slightly positive charged areas of a molecule.

water molecules have special properties as a result of hydrogen bonding

some of the properties include cohesion and adhesion- cohesion involves the surface tension, which is high in water.

Carbohydrates

a group of organic compounds that provide the main source of energy for cells.

Lipids

Nonpolar molecules that serve multiple functions in a cell including membrane structure.

Proteins

Perform a variety of structural and functional roles in cells. they are made up of monomers called amino acids

organelles

components in a cell that carry out specialized roles in the cell.

Biogeochemical cycles

processes that make inorganic nutrients available to living cells and can be disrupted by human activities leading to eutrophication and hypoxic and anoxic zones in aquatic ecosystems.

eutrophication

excessive nutrients in a lake or other body of water, usually caused by runoff of nutrients from the land, which causes a dense growth of plant life

hypoxic

oxygen deficiency in an aquatic ecosystem

anoxic

severe hypoxia or total lack of oxygen

polymers

large molecules constructed of smaller molecules or monomers

monomers

the smaller units of which larger molecules or polymers are made

hydrolosis reactions

reactions that break down polymers to form monomers

condensation (dehydration synthesis)

reactions thatbond monomers together to form polymers

how soap works

polar head bonds to water, nonpolar tail bonds to and damages lipids/membrane of bacteria and viruses/nonpolar substances. since the heads are bonded to the water, it is easier to wash bacteria and viruses off the hands.

water's polarity

helps it to dissolve other polar substances (like dissloves like)