BIOL110: EXAM #2

nucleus

contains DNA

nucleolus

makes RNA, subunits of ribosomes, contains genetic info

nucleus

contains DNA

nucleolus

makes RNA, subunits of ribosomes, contains genetic info

nuclear envelope

has nuclear pores, inner/outer membrane; regulates transportation of molecules between nucleus & cytoplasm

nuclear lamina

net-like protein filaments, supports envelope

ribosomes

protein synthesis; made in nucleolus

free ribosomes

suspended in cytosol; first step of sugar breakdown

bound ribosomes

attached to the ER; made proteins to destined to be inserted in the membrane

ER

biosynthetic factory —> continuous with outer membrane envelope

ER structure

cisternae (sacs), and lumen (cavity)

smooth ER

no ribosomes, lipid synthesis, Ca²⁺ storage, metabolizes carbs, detox poisons/drugs

rough ER

ribosomes, makes proteins, adds carbs, makes phospholipids

golgi apparatus

warehouse of the cell; modify ER proteins, polysaccharide synthesis, sorting/packaging vesicles

golgi structure

flattened stacks of membranous sacs

mitochondria

powerhouse of the cell, cellular respiration

mitochondria structure

inner/outer membrane, cristae (folds in the inner membrane, ATP synthesis) and matrix (inside gel; enzymes/mDNA/ribosomes

lysosomes structure

membranous sacs with hydrolytic enzymes —> made in RER; acidic on the inside

lysosomes

phagocytosis/autophagy (recycling of organic material)

peroxisomes

breaks down fatty acids

peroxisome oxidation

1. RH₂ + O₂ —> H₂O₂

2. H₂O₂ —> 2 H₂O + O₂

chloroplast

photosynthesis

chloroplast structure

inner/outer membrane, stroma (liquid on inside), thylakoid (chlorophyll)

cytoskeleton

network of fibers essential to cellular function/structure, organizes, supports, and motility

motor proteins

interact for cell motility

microtubules

hollow tubes, 25 nm, a & b tubulin

microtubules function

cell shape, cell motility (motion of flagella and cilia), vesicle highways

intermediate filaments

coiled protein cables, 8-12 nm, protein vary (keratin)

intermediate filaments structure

cell shape, nuclear lamina, organelle positioning

microfilament

two intertwined protein strands, 7 nm, made of actin

microfilaments structure

muscle contraction —> myosin, cytoplasmic streaming, cell crawling, animal cell division

ECM

adhesion, support, movement, regulation of the extracellular side of the cell; acts like the glue

components of ECM

collagen, fibronectin, proteoglycan complex, integrins, microfilaments

cell junction

tight junctions, desmosomes, gap junctions

tight junctions

prevents leakage between cells

desmosomes

fastens the cells together

gap functions

cytoplasmic channel between adjacent cells

plasma membrane

selective boundary surrounding all cells; selectively permeable, acts as a gate-keeper, creates different chemical environments

lipids

phospholipids, amphipathic, cholesterol —> 4 fused rings structure

proteins

integral: span membrane, peripheral: loosely associated with membrane

variety of proteins function

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and ECM

carbohydrates

short, branched chains; extracellular (outside) side of membrane (glycoproteins and glycolipids)

passive transport

high to low, no E required, down concentration gradient

simple diffusion

molecules slip between phospholipids (CO₂ & O₂ )

facilitated diffusion

channel proteins (aquaporins, ions), carrier proteins (glucose, amino acids)

osmosis

low solute concentration to high solute concentration to drive the movement of water

hypotonic

lysed/turgid —> solute outside is lower

isotonic

normal/flaccid —> plant wilts

hypertonic

shriveled/plasmolyzed —> solute outside is higher

active transport

low to high, E required, against concentration

sodium-potassium pump

3 sodium out, 2 potassium in

bulk transport

moving large molecules across membrane

exocytosis

cell secretes molecule by fusion of vesicle with pl. membrane —> transport of protein

endocytosis

cells take in molecules & particulate matter by forming new vesicles from pl. membrane —> phagocytosis, pinocytosis, RME (LDL cholesterol uptake)

metabolism

sum of organism’s chemical reactions

metabolic pathways

specific molecules altered in series of defined steps resulting in certain products —> each step catalyzed by enzyme

anabolism

biosynthetic pathways (monomers —> polymers), consumes E, synthesis proteins from amino acids

catabolism

breakdown/degradative pathways (polymers —> monomers), releases E, cellular respiration

exergonic

energy released, spontaneous (downhill, higher in reactant)

endergonic

energy required, non-spontaneous (uphill, higher in products)

cells 3 main kinds of work

chemical work, transport work, mechanical work

ATP

energy currency of the cell

adenosine triphosphate

ribose, adenine, 3 phosphate groups

ATP hydrolysis

ATP —> ATP P_i (exergonic reaction)

enzyme

catalyst that speeds up reaction, lowers activation energy

enzyme features

catalysts, “ase”, proteins have enzymes, active site, highly specific

active site

pocket / groove for substrate interactions & catalysis

substrate

reactant on which enzyme works

enzyme-substrate complex

formed up E —> S interactions

first step of enzymatic work

substrate enters active site

second step of enzymatic work

substrate are held in active site by weak interactions

third step of enzymatic work

active site lowers E_A

fourth step of enzymatic work

substrates are converted to products

fifth step of enzymatic work

products are released

sixth step of enzymatic work

active site is available for new substrate

activation energy

E_A —> E required to start reaction

catabolic pathways

transfer of electrons (e-) during chemical reactions - released stored E - drives ATP synthesis

oxidation-reduction reactions

redox reactions (OIL RIG)

aerobic respiration

cellular respiration

glucose catabolism

oxygen consumed with organic fuel

glycolysis

2 phases: E investment & E payoff

E investment

uses ATP

E payoff

yields ATP

location of glycolysis

cytoplasm

glycolysis inputs

1 glucose (6 carbons), 2 ATP, 2 NAD⁺ (electron carrier)

glycolysis net yield

2 pyruvate (3 carbons), 2 ATP (4-2 =2 ), 2 NADH (stored E to make ATP)

substrate-level phosphorylation

enzymatic transfer of phosphate group from organic substrate to ADP

pyruvate oxidation

catalyzed by pyruvate dehydrogenase

location of pyruvate oxidation

mitochondrial matrix

pyruvate oxidation reactions

1. carboxyl group fully oxidized to CO₂

2. 2-C fragment oxidized & e- transferred to NAD⁺ to NADH

3. CoA (coenzyme A) attaches to 2-C intermediate via S atom —> acetyl CoA

pyruvate oxidation inputs

2 pyruvate

pyruvate oxidation net yields

2 acetyl CoA, 2 NADH, 2 CO₂ (NO ATP)

location of kreb cycle

matrix

kreb cycle inputs

2 acetyl CoA

kreb cycle net yields

2 ATP, 6 NADH, 2 FADH₂, 4 CO₂

electron transport chain

f(x) est. H⁺ gradient —> “hot potato”

location of ETC

cristae

final e- acceptor

O₂

NADH & FADH₂

where electrons come from during ETC

location of chemiosmosis

cristae

chemiosmosis reaction

down concentration gradient through ATP synthase —> uses proton motive force

ATP yield during chemiosmosis

oxidative phosphorylation