exam 1 cell structure

Nucleus

largest organized cell component, enclosed double layered, contains dna

DNA

contained in nucleus, directs protein synthesis, serves as genetic blueprint during cell replication

cytoplasm

portion of cell interior that’s not the nucleus

cytosol

largely water with dissolved protein, sugars and other solutes

organelles

distinct, highly organized membrane enclosed structures

cytoskeleton

connective tissue components that give structure/shape to cell

endoplasmic reticulum ER

protein and lipid synthesis

smooth ER

lipid synthesis

rough ER

protein synthesis, has ribosomes attached

golgi complex

process raw materials into finished products

process of protein synthesis

Rough ER synthesizes proteins

Smooth ER packages the secretory product into transport vesicles

Transport vesicles fuse with golgi complex, open up and empty their contents into the closest Golgi sac

Newly synthesized protein travels through layers of golgi complex and modifies the raw proteins into final form and directs the finished products to their final destination

The secretory vesicles is secreted via exocytosis upon appropriate stimulation

exocytosis

secretory vesicles fuses with membrane, releasing to the cell exterior

endocytosis

material from cell exterior are enclosed in segment of plasma membrane, pinches off

lysosome

contains digestive enzymes, digest toxins and nonuseful tissue

peroxisomes

detoxify harmful substances, neutralize dangerous free radicals by donating electron

free radicals

have unpaired electrons that could cause damage to cell

mitochondria

major site of atp production

flaws in mitochondrial dna leads to

muscle weakness, incoordination, seizures, blindness, hearing loss

DNA structure

double helix

dna sides are made out of

phosphate and sugar

what is phosphate and sugar in dna held together by

hydrogen bonds

dna replication pattern

antiparallel

why does dna replication need to be anti parallel

because it can only go in the direction of 5’ to 3’

in dna adenine pairs with

thymine

guanine pairs with

cytosine

in rna adenine pairs with

uracil

transcription

mRNA of DNA segment is copied

translation

tRNA reads mRNA to make protein

tRNA

brings amino acids to ribosome to make protein

ribosome

reads mRNA, cary out protein synthesis

where is ribosomes found

free in the cytosol or attached to rough ER

translation from mRNA to protein

mRNA is created in nucleus

mRNA leaves nucleus and attaches to ribosome, translation begins

tRNA puts together anticodon to complementary amino acids on ribosome

Ribosome moves along the mRNA a new amino acid is added to the growing protein chain

Released tRNA reenters cytoplasmic pool of free tRNA

primary protein

sequence of amino acids

secondary protein

putting 2 amino acids together, alpha helix, beta pleated sheet

tertiary protein

more alpha helix/betapleated sheets together, polypeptide chain

quaternary protein

formations of proteins with more than one polypeptide chain

fibrous protein

structure, rigidity, form, collagen

globular protein

more functional, insulin

mixed protein

fibrous tail and globular head

cytoskeleton

fibrous protein, mechanical support, intracellular transport, helps with contraction and movement of cell

what is the cell membrane composed of

phospholipids and proteins

phospholipid

most common membrane lipid, very flexible and allow for membrane to be fluid,

cholesterol

more stable, reduces membrane fluidity and makes membrane stronger

glycolipids

lipids with sugar residue, makes cell float and involved in cell to cell interaction

peripheral protein

only on surface of membrane, enzymes, regulator

integral proteins

penetrate lipid core, are transporters/carriers

transmembrane protein

span entire membrane, channels

glycolipids and glycoproteins

bound to membrane, cell surface marker, makes up glycocalyx

diffusion rule

molecules will move down concentration gradient until uniform distribution

diffusion rule with ions

ions are attracted to opposite charges

pores

always open, water and K

channels

respond to signals to let something in

carriers

assists larger solutes across membrane

simple diffusion

larger the gradient, the faster the diffusion

carrier mediated diffusion

carrier binds to molecule to cross membrane, rate of diffusion goes up until all carriers are saturated

passive transport

along concentration gradient

active transport

requires energy ATP to move against concentration gradient

osmosis

diffusion of water

how does the body regulate water movement?

manipulating solute concentration

osmotic pressure

amount of pressure required to counteract movement of water

resting/leaking channel

always open

voltage gated channel

opens in response to change in membrane potential

ligand gated channels

open in response to specific neurotransmitter

signal gated channel

open in response to specific intracellular molecule

gap junctions

allow for direct communication between cells

tight junctions

allow molecule transportation only through cells

hormones

chemical messenger carried by blood to distant targets

paracrine

released by cell to affect another cell close by

autocrine

released by cell that binds back to self

desmosomes

binds cell together for strength

potassium is high where

inside

sodium and calcium is high where

outside

resting membrane potential

-40 to -90

hypokalemia

low K in ECF, cell becomes more negative, harder to excite

hyperkalemia

high K in ECF, cell becomes more positive, cell is more easily excited

threshold

cell will fully depolarize if threshold is reached

overshoot

massive influx of NA causes membrane potential to become super positive

afterpotential/hyperpolarization

massive exit of K ions, cell briefly becomes super negative