BI 231Z - Midterm 1 Biomolecules

homeostasis

a state of equilibrium, maintaining a stable internal environment

homeostatic regulation

physiological systems respond to changes to function within a normal range

autoregulation/intrinsic control

receptor, control center, and effector all in one place

extrinsic control

control center signals effector through nervous or endocrine signals

negative feedback loop

returns to state of equilibrium

positive feedback loop

pushes farther and farther from equilibrium

biomolecules/organic compounds

carbon based molecules. contain covalent bonds between C, H, O, N, P

dehydration synthesis

joining two monomers into a dimer

hydrolysis

breaking down a dimer into two monomers

carbohydrates

broken down by cells for fuel. simple and complex sugars. (eg: glucose, maltose, glycogen)

lipids

nonpolar, hydrophobic. can be saturated or unsaturated. (eg: fatty acids, glycerol, steroids, phospholipids)

proteins

complex 3D molecules. made up of amino acids. (eg: keratin, collagen, enzymes)

enzymes

catalyze chemical reactions, lower activation energy. exhibit substrate specificity

nucleic acids

store genetic information. make up DNA, RNA

diffusion

movement of molecules form an area of high concentration to an area of low concentration

phospholipid bilayer

double layer of phospholipid molecules (hydrophilic heads face outwards, hydrophobic fatty acid tails face inwards). studded with proteins.

cytoplasm

all materials inside the cell and outside the nucleus

cytosol

intracellular fluid. (water and dissolved materials - nutrients, ions, proteins, waste products)

organelles

structures with specific functions

mitochondria

provides cells with energy for life. requires oxygen and organic substrates. generates carbon dioxide and ATP.

ATP (adenosine triphosphate)

energy for cells. made on demand by enzymes (anaerobic) or in mitochondria (aerobic). cannot be stored or transferred between cells

cytoskeleton

structural proteins for shape and strength. internal scaffolding, anchors other organelles

cilia/flagella

move fluids across the cell surface/move cell

nucleus

cell’s control center. contains DNA

free ribosomes

builds proteins for intracellular use

fixed ribosomes/rough ER

builds proteins for extracellular use (secretion)

golgi apparatus

packages products for secretion

chromatin

loosely coiled DNA (cells not dividing)

chromosomes

tightly coiled DNA (cells dividing)

DNA

instructions for every protein in the body

gene

DNA instructions for one protein