Exam 1

Homeostasis

process by which organisms maintain a relatively stable internal environment

Components of a feedback system

receptor, control center, effector

receptor

monitors controlled condition and sends inputs to control center

control center

receives input from receptor & determines appropriate response

effector

provides the means for the control center's response to the stimulus

positive feedback

Feedback tends to reinforce the effects of the stimulus

negative feedback

feedback tends to negate the effects of the stimulus

What kinds of bonds are present within water molecules?

polar covalent

properties of water

solvent, cohesion, adhesion

electrolytes

substances that release ions in water

acids

compounds that form hydrogen ions when dissolved in water

bases

Compounds that reduce the concentration of hydrogen ions in a solution

pH

the concentration of hydrogen ions in a solution

low pH

acidic

high pH

basic

buffer function

resist changes in pH

buffer

mixture of weak acids or bases and their conjugates

hydroxyl group

-OH

sulfhydryl group

-SH

carbonyl group

C=O

carboxyl group

COOH

ester group

RCOOR

phosphate group

PO4

amino group

NH2

carbohydrate functions

primary source of energy

carbohydrate structure

carbon, hydrogen, and oxygen in a 1:2:1 ratio

Polysaccharides

Carbohydrates that are made up of more than two monosaccharides

dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule

Hydrolysis

Breaking down complex molecules by the chemical addition of water

lipid functions

energy storage, regulating and signaling, insulating and protecting

triglyceride structure

glycerol and 3 fatty acids

phospholipid structure

2 fatty acids, 1 glycerol, 1 phosphate group

steroid structure

4 fused rings

protein functions

structure, communication, receptors, transporters, enzymes, protection

amino acid structure

carboxyl group, amine group, functional group

polypeptide chain

long chain of amino acids linked by peptide bonds

peptide bonds

bonds between amino acids formed by dehydration synthesis

primary structure

sequence of amino acids

secondary structure

alpha helices and beta sheets

tertiary structure

folding and coiling due to interactions among functional groups

quaternary structure

the association of two or more polypeptide chains

DNA function

stores genetic information

RNA function

protein synthesis

nucleic acid structure

phosphate group, 5-carbon sugar, nitrogenous base

ATP structure

adenine, ribose, 3 phosphate groups

ATP function

transfer and storage of energy

3 main parts of cells

plasma membrane, cytoplasm, nucleus

structure of plasma membrane

phospholipid bilayer with hydrophobic tails and hydrophilic heads

Functions of membrane proteins

transport, enzymes, receptors, join membranes, structure, cell identity markers

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

electrochemical gradient

The combination of forces that acts on membrane potential

osmosis

Diffusion of water through a selectively permeable membrane

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

transport maximum

transport rate when all carriers are occupied

hypotonic

surrounding medium has less solute than the cell interior

hypertonic

surrounding medium has more solute than the cell interior

isotonic

surrounding medium has the same solute as the cell interior

filtration

passive process where liquid flows due to hydrostatic pressure

primary active transport

Active transport that relies directly on the hydrolysis of ATP

secondary active transport

energy is provided indirectly

vesicular transport

Transport of large particles and macromolecules across plasma membranes

cytoskeleton function

strength and support, movement of cellular structures and materials

endoplasmic reticulum function

transports synthesized proteins and lipids to other parts of the cell

lysosome function

intracellular digestion

Mitchondria function

ATP production

Golgi apparatus function

modifies and packages proteins and lipids

nucleus function

Control center of the cell, stores genetic material