CELL BIO EXAM 1

Cell Theory

1) All organisms are composed of one or more cells 2) the cell is the structural unit of life 3) cells arise only by the division of pre-existing cells.

What limits cell size?

surface-area-to-volume-ratio

What gives a cell function?

structure

when does cell differentiation occur?

during embryonic development

4 major tissue types

connective, muscular, nervous, epithelial

connective tissue

binds and supports body parts

muscular tissue

moves the body and its parts

nervous tissue

conducts nerve impulses

epithelial tissue

covers body surfaces; lines body cavities

examples of connective tissue

adipose tissue, compact bone, hyaline cartilage

epithelial tissue shapes

simple, psuedostratified columnar, stratified, squamous, cuboidal, columnar

radioisotopes

unstable isotopes

properties of water

polarity, hydrogen bonding, high heat of vaporization, cohesion, adhesion, high heat capacity

cohesion

water molecules cling to each other through hydrogen bonds

adhesion

water molecules cling to surfaces, like blood vessels

Sugar is the building block for..?

polysaccharides and oligosaccharides

Fatty acids are the building block for..?

fats and membrane lipids

amino acids are the building blocks for..?

proteins

nucleotides are the building blocks for..?

nucleic acids

polysaccharides(complex carbs)

long polymers of glucose subunits

polysaccharide in plants

starch

polysaccharide in animals

glycogen

structural polysaccharide in plants

cellulose

common carbohydrate isomers

glucose, galactose, fructose

common types of lipids

triglycerides, phospholipids, steroids

what are the two forms of triglycerides

fats and oils

function of triglycerides

energy storage, insulation, cushioning

emulsifier

molecules that surround triglycerides and disperse(emulsify) them

What is the process that allows for enzymes to break down triglycerides?

emulsification

function of waxes

prevent the loss of moisture from body surfaces

common grouping of amino acids

acidic, basic, uncharged polar, nonpolar

optical isomer

same as a stereoisomer

peptide bond

amide linkage which connects amino acids

levels of proteins organization

primary, secondary, tertiary, some have quaternary

primary structure

the linear order of amino acids

secondary structure

localized folding (alpha helix, beta pleated sheet)

tertiary structure

3D shapes determined by all three bonds types

quaternary structure

a combination of more than one polypeptide, each with its own primary, secondary, and tertiary structure

nucleotides

subunits of DNA and RNA

nitrogenous bases

pyrimidines or purines

pyrimadine

uracil, cytosine, thymine

purine

adenine, guanine

composition of nucleotide

nitrogen-containing base, a five-carbon sugar, one phosphate group

glycosidic linkage

base-sugar linkage

central dogma

describes the unidirectional flow of genetic information from DNA to RNA to protein

unambiguous

each triplet specififes only one amino acid

degenerate

a given amino acid can be specified by more than one  triplet codon

commaless

the genetic code being continuous without any punctuation or gaps between codons

nonoverlapping

any single ribonucleotide within mRNA is part of one triplet

nearly universal

a single coding dictionary is used by viruses, prokaryotes, archea, and eukaryotes

reading frame

continuous sequence of nucleotides

what is encoded for by a single codon?

tryptophan and methionine

protein targeting

the mechanism by which a cell transports proteins to the appropriate positions in the cell or outside of it

where are internal targeting peptides?

found in the peptide chain

export from nucleus signal sequence

leu-ala-leu-lys-leu-ala-gly-leu-asp-Ile

ways proteins can move between compartments

gated transport, transmembrane transport, vesicular transport

what defines the shape of a protein

amino acid sequence

3 types of covalent bonds in protein folding

electrostatic attractions, hydrogen bonds, van der waals attractions

what forces help proteins fold into compact conformations?

hydrophobic forces

what can act as a garbage disposal

isolation chamber

things proteins can assemble into

filaments, sheets, or spheres

what type of bond stabilizes extracellular proteins?

covalent cross-linkages

binding sites allow protein to interact with..?

specific ligands

how proteins work

enzymes chemically transform the ligands to which they bind

hydrolase

general term for enzymes that catalyze a hydrolytic cleavage reaction

nuclease

breaks down the nucleic acids by hydrolyzing bonds between nucleotides

protease

breaks down proteins by hydrolyzing peptide binds between amino acids

ligase

joins two molecules together; DNA -ase joins two DNA strands together, end to end

isomerase

catalyzes the rearrangement of bonds within a single molecule

polymerase

catalyze polymerization reactions such as the synthesis of DNA and RNA

kinase

catalyses the addition of phosphate groups to molecules

phosphatase

catalyses the hydrolytic removal of a phosphate group from a molecule

oxido-reductase

enzymes that catalyze reactions in which one molecule is oxidized and the other is reduced

common names for oxido-reductase

oxidases, reductases, dehydrogenases

ATPase

hydrolyzes ATP

What do some proteins require to function?

tightly bound small molecules

feedback inhibition

when other molecules regulate the catalytic activities of enzymes

allosteric enzyme

enzyme which binds to a different site on a molecule, causing it to change shape

how many binding sites do allosteric enzymes have?

two or more (which influence one another)

how can a regulatory ligand effect a bond?

change the equilibrium between two protein conformations

what can control protein activity by causing a conformational change?

phosphorylation

what controls the location and interactions of proteins?

covalent modifications

what allows for motor proteins to produce directed movements in cells?

ATP Hydrolysis

what does transcription produce?

RNA that is complementary to one strand of DNA

where are eukaryotic mRNAs processed

in the nucleus

what is the process that removes introns from pre-mRNA?

RNA splicing

where does RNA synthesis and processing take place?

within membraneless compartments within the nucleus

mRNA

code for proteins

Ribosomal RNA (rRNA)

form the cre of the ribosomes structure and catalyze protein synthesis

microRNA (miRNA)

regulate gene expression

transfer RNA (tRNA)

serve as adaptors between mRNA and amino acid during protein synthesis

small interfering RNA (siRNA)

provide protection froom viruses and proliferating transposable elements

long noncoding RNA (lncRNA)

act as scaffolds and serve other diverse functions

other noncoding RNA

used in RNA splicing, gene regulation, telomere maintenance, and many other processes

what requires the assistance of a collection of accessory proteins?

eukaryotic RNA polymerase

RNA polymerase I

most rRNA genes

RNA polymerase II

all protein-coding genes, miRNA genes, plus genes for other noncoding RNAs

RNA polymerase III

tRNA genes, 5S rRNA gene, genes for many other small RNAs

where is eukaryotic mRNA processed?

within the nucleus

parts of the endomembrane system

nuclear envelope, endoplasmic reticulum, Golgi apparatus, vesicle, lysosome, plasma membrane