Bio 151 exam 1 (2)

functions of carbohydrates

contain energy (chemical bonds)

transport energy

store energy

can be structural

structure of carbohydrates

...

disaccharides

carbs formed by adding two monosaccharides together by a condensation reaction (dehydration synthesis). reversal is hyrdolysis

important disaccharies

sucrose (glucose + fructose; primary transport sugar in plants)

maltose (2x glucose; product of starch hydrolysis)

lactose (glucose + galactose)

glycogen

important polysaccharide

glucose based

long-term, quickly available energy

energy storage for animals

irregular branching pattern

starch

important polysaccharide

energy for plants

regular branching pattern

cellulose

important polysaccharide

polymer of beta-glucose

used in plant cell and bacteria cell walls

chitin

important polysaccharide

used in insect exoskeletons

definition of lipids

a class of compounds defined by properties, not composition

are fats and "fat-like" substances

hydrophobic

typically just carbon and hydrogen (can have small amounts of oxygen)

primary types of lipids

fats and oil

sterols

fats and oils

super high density, long-term energy storage

interaction with water defines boundaries in cells (builds membranes)

sterols

act as biological signals in cells

stiffen membranes

maintains fluidity (prevents fatty acids from crystallizing)

fatty acids

long carbon/hydrogen chains

made from two-carbon units so are often made of 16 or 18 carbons

fat

a large molecule constructed from 2 kinds of smaller molecules: glycerol and fatty acids

glycerol

an alcohol

each of its 3 carbons bears a hydroxl group

triglycerides

the resulting fat that consists of 3 fatty acids linked to one glycerol molecule

phospholipid

2 fatty acids + a phosphate group + something else on a glucose molecule

no O or N to make it polar

hydrophobic on one end and hydrophilic on the other

aquaporin

a protein that allows water to pass through a membrane

structure of a protein

a polymer of amino acid monomers (amino acids hooked in a chain)

a carbon with an amino group on the right, a carboxyl group on the left, a hydrogen on the bottom, and a variable group ('R') on the top

definition of proteins

chemically defined

amino acids linked together by peptide bonds

bonds form by removal of water

properties of proteins depend on which amino acids are used and in what order

amino acids

can be polar or nonpolar

positively or negatively charged

many exist, but only 20 are used in proteins

micelle

...

how to "read" proteins

"read" from the amino terminus to the carboxy terminus

levels of protein structure

primary

secondary

tertiary

quaternary

primary structure of proteins

the basic chain of amino acids

predicts the structure of 2nd and 3rd

secondary structure of proteins

hydrogen bonds form between the backbones

form alpha helix (hemaglobin) and beta sheets (silk)

doesn't require energy

tertiary structure of proteins

all other types of folding due to interactions between side chains

side chains bond to each other

quaternary structure of proteins

the binding of proteins to other proteins

jobs of proteins

catalysts

structural

transport

signaling

proteins at catalysts

enzymes

if ends in "-ase" most likely an enzyme

allow reactions to proceed faster or slower, do not cause reactions

structural proteins

collagen

keratin

transport proteins

hemaglobin

signaling proteins

hormones: insulin, vasopresin

not all signals are proteins (estrogen and testosterone are made from cholesterol)

nucleic acids

nuleotide monomers linked into a polymer forming a SUGAR-PHOSPHATE backbone

backbone = a 5-carbon sugar + a phosphate group

nitrogenous bases

two families:

pyrimidines- all have one ring (cytosine, thymine, uracil)

purines- have two rings (adenine, guanine)

A-T (or U in RNA)

C-G

pentose sugars in nucleic acids

DNA: deoxyribose: stable, lasts a long time, has an H

RNA: ribose: unstable, doesn't last long, has an OH

phosphodiester linkage

bonds nucleic acids through a condensation reaction that bonds the phosphate on 5' of one 5-carbon to the carbon on 3' of another 5-carbon

RNA

usually single stranded

some can be enzymes

pentose (sugar): ribose

nitrogenous bases: A, U, C, G

DNA

usually double helix

none are enzymes

more stable than RNA

good for storing and replicating information

can be used as a template to make RNA

pentose: deoxyribose

nitrogenous bases: A, T, C, G

eukaryotic cells

nuclear envelope enclosing DNA (linear model)

membrane-bound organelles (compartmentalized)

prokaryotic cells

no nuclear envelope

circular DNA, found in the nucleoid region, and accessory circular DNA molecules called plasmids

no endomembrane system (or very simple)

nucleus

membrane bounds region within the cell that contains LINEAR chromosomes (DNA, proteins)

mitochondria

produces chemical energy from sugars

two membranes, outer is smooth, inner is folded

contains DNA and ribosomes

chloroplasts

in plants and some protists

site for production of energy from sunlight (photosynthesis)

two membranes

has DNA and ribosomes

endoplasmic reticulum

synthesis and modification of proteins and lipids (makes things within a cell)

is a network of membrane-enclosed tubes and disks

connected to the outer membrane of the nucleus

golgi apparatus

modification of proteins; synthesis of some polysaccharides (plants)

lysosome/vacuoles

degradation; storage

proteins in cell membranes

attached to or embedded in a membrane

embedded = transmembrane proteins

integral membrane protein

runs through the membrane

hydrophobic on the inside

peripheral membrane protein

on the surface of the membrane

hydrophilic properties

membrane function

act as a barrier between the cytoplasm and the outside world

are permeable to some molecules but the others (semi-permeable)

semi-permeable nature leads to osmosis

osmosis

the movement of water across a semi-permeable membrane

osmotic pressure

the pressure required to counteract osmosis

compensated by hydrostatic pressure

(concentration of dissolved stuff)

hydrostatic pressure

...

hyptonic solution

outside solution has higher h2o concentration than inside the cell

animal cells: lyseed: too much water moves into the cell and it bursts

plant cells: turgid (normal): solid cell wall prevents cell from over-expanding and exploding

isotonic solution

same concentration of water inside and outside the cell

animal cells: normal: no net direction for the flow of h2o

plant cells: flaccid: fine, but the cell isn't quite as solid

hypertonic solution

more salt dissolved outside the cell than inside

animal cells: shriveled: h2o leaves the cells so cell shrinks

plant cells: plasmolyzed: cell wall doesn't move but plasma & cytoplasm shrink

transport proteins

span the membrane and allow specific ions and polar molecules to pass through without contacting the lipid bilayer

specific for the substance it translocates (moves)

channel proteins

function by having a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane

aquaporins

channel proteins that facilitate the entry of water molecules

carrier proteins

hold on to their passengers and change shape in a way that shuttles them across the membrane

symporter

...

antiporter

...

electrochemical gradient

transporters allow compounds to move across a membrane, this says if it's ok

if the compound doesn't have a charge (e.g. glucose) then this is irrelevant

exocytosis

fusion with the cell membrane to get stuff out of the cell

the process by which the cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane

endocytosis

pinching off with the cell membrane to get stuff in and out of the cell

the cell takes in biological molecules and particulate matter by forming new vesicles from the plasma membrane

phagocytosis

a type of endocytosis

a cell engulfs a particle by wrapping a pseudopodia around it and packaging it within a food vacuole

active transport

pumping a solute across a membrane against its gradient

sodium-potassium pump

exchanges Na+ for K+ across the membrane of animal cells

cotransport

coupling of the "downhill" diffusion of one substance with the "uphill" transport of another against its own concentration gradient

plasmolyzed

...

fluid mosaic

the membrane is a fluid structure with a "mosaic" of various proteins embedded in or attached to a phospholipid bilayer

facilitated diffusion

the phenomenon where molecules and ions diffuse passively across the membrane with help from transport proteins

rough ER

has ribosomes on its surface; a place for protein synthesis

transmembrane and secreted proteins are made outside then inserted inside

secreted proteins then move to the golgi apparatus

golgi apparatus

a stack of flattened membrane-bound discs

process secreted proteins

synthesize polysaccharides

has a cis face and a trans face

cis face

side of a golgi apparatus that's located near the ER

receives transport vesicles from the ER

trans face

side of the golgi apparatus where synthesized things leave

creates vesicles that pinch off and go to other parts of the cell

structures that make up the cytoskeleton

all protein based

microtubules (made of tubulin)

microfilaments (made of actin)

intermediate filaments (made of keratin-type proteints)-not in plants

main microtubule functions

maintenance of cell shape

organelle movement

chromosome movement in cell division

cell motility (makes up cilia and flagella)

movement mediated by microtubules

-by extension or shortening (adding or removing tubulin molecules)

-by using attached proteins and ATP to "walk" vesicles along microtubules

microfilaments (actin filaments)

double spiral made of actin proteins

maintain and change cell shape

muscle contractions

cytoplasmic streaming (churns cytoplasm like blood)

cell motility

cell division

cristae

...

grana

...

thylakoid

...

entropy

a way to measure disorder and randomness

means that life requires energy

spontaneous process

does not need energy input to occur

it increases the entropy of the universe

biological order

life implies complex levels of organization

life is ordered so it must have energy input

1st physical law of thermodynamics

entropy of the universe tends to increase

disorder just happens; keeping things highly ordered takes a large amount of energy

Gibbs free energy

portion of a system's energy that can perform work in a cell

change in Gibbs free energy

the amount of energy used up tells you if the reaction was spontaneous or not

if product is > A+B, the cell used energy

if product is < A+B, the reaction was spontaneous

as free energy increases, Gibbs increases (larger #)

as free energy decreases, Gibbs decreases (smaller #)

anabolism

triggering metabolism to build something up

catabolism

breaking things down to release energy

how to know if a chemical reaction will occur spontaneously

delta G = G(final state) - G(initial state)

delta G

exergonic reaction

a spontaneous reaction; had enough energy already there

endergonic reaction

a reaction that required energy; had to make energy because there wasn't enough there originally

activation energy

found in spontaneous reactions

the energy required to "activate" the molecules; get them to the transition state from where the reaction will occur spontaneously

the amount of Ea = the rate of the reaction

increase Ea = slower reaction

catalyst

makes a spontaneous reaction occur faster by decreasing the amount of Ea needed

active site

the place in an enzyme where the reaction occurs

exact right shape for the substrate

control of enzyme activity

normal binding

competitive inhibition

noncompetitive inhibition

normal binding

a substrate can ind normally to the active site of an enzyme