Cellular Biology - Midterm 2

Question 1

Prokaryotes
- peptidoglycan
- pili
- binary fission

Answer 1

Unicellular
Small
No nucleus
Circular DNA
No organelles / cytoskeleton
Small ribosomes
Peptidoglycan: cell walls
Flagella rotates using H+ gradient
Has pili: for adhesion and sexual exchange
Binary fission: how prokaryotes divide
ex) bacteria and archaea

Question 2

Eukaryotes
- mitosis and meiosis

Answer 2

uni/multicellular
Larger
Contains nucleus w/ DNA
DNA as linear chromosome protein complex
Many organelles
3 types of fibers in cytoskeleton
Large ribosomes
Cell walls in plant cells (cellulose) and fungi (chitin)
Flagella move in whip-like motion , composed of microtubules
No pili
Mitosis and meiosis: how eukaryotes divide
ex) animals, fungi, plants, protists

Question 3

Schekman

Answer 3

discovered genes important for protein secretion by studying yeast

Question 4

Fleming

Answer 4

discovered antibiotic penicillin

Question 5

Van Leeuwenhoek

Answer 5

believed sperm cells contained mini humans

Question 6

Nucleus
- chromosomal DNA

Answer 6

Double membrane organelle
Holds all chromosomal DNA: packed chromatin fibers with equal mass of protein histine
Communicates with cystol

Question 7

Nucleolus

Answer 7

assembles ribosomes

Question 8

nuclear envelope

Answer 8

double membrane supported by nuclear lamin

Question 9

nuclear pores
- NLS
- importin

Answer 9

Nuclear pores: allow transport in / out of nucleus
NLS: amino acid tag required for transport
Importin: recognizes amino acid tag

Question 10

Mitochondria
-inner membrane
- cristae
- matrix

Answer 10

Creates ATP (energy)
Double membraned organelle
Inner membrane: folded into cristae to increase surface area, site of electron transport
Matrix: site of TCA cycle, contains many enzymes

Question 11

chloroplasts
- thylakoid
- grana
- stroma

Answer 11

Double membrane organelle
Found in plants only
Conducts photosynthesis
Thylakoid: where light rxns occur
Grana: stacks of thylakoids
Stroma: where dark rxns occur (ex: sugar synthesis)

Question 12

endosymbiosis

Answer 12

engulfed prokaryotes, resulted in mitochondria and chloroplasts

Question 13

centriole

Answer 13

( only in animal cell) organizing center for facilitating cell division

Question 14

Plant cell
Cell wall:
Chloroplast:
Vacuole:

Answer 14

structural support
: for photosynthesis
: storage and provides turgor pressure

Question 15

Plasma Membrane

Answer 15

phospholipid bilayer surrounding cell
Contains proteins that allow for transport in / out of the cell

Question 16

Endoplasmic reticulum

Answer 16

Specializes in synthesis and transport of lipids and membrane proteins

Question 17

rough er

Answer 17

engaged in protein synthesis; has ribosomes

Question 18

SMOOTH ER

Answer 18

lipid metabolism, detoxifies toxins; no ribosomes

Question 19

lysosomes

Answer 19

Single membrane vesicle
Intracellular digestion

Question 20

Peroxisomes

Answer 20

Single membrane vesicle
Generate and destroy hydrogen peroxide

Question 21

Endomembrane System

Answer 21

ER + golgi + lysosomes + peroxisomes

Question 22

cytoskeleton

Answer 22

Array of protein filaments in cystol that give cell shape and movement
Include microtubules, microfilaments, and intermediate filaments

Question 23

microfilaments (actin filaments)
- pseudopodia
- cytokinesis

Answer 23

Largest filament
Double helix structure
Polar
Actin subunit
Resists pull tension
Pseudopodia: moves cells via cell crawling
Cytokinesis: divides animal cells in two
determine shape
whole cell movement

Question 24

intermediate filaments

Answer 24

Keratin / lamin fibers wound into thicker cables
Intermediate sized filament
Resists pull tension
Anchor nucleus and other organelles

Question 25

microtubules

Answer 25

Polar hollow tube composed of alpha and beta tubulin dimers
Determine position of membrane bound organelles and direct intracellular transport

Question 26

Dynamics
- treadmilling
- dynamic instability

Answer 26

Microtubules and actin filaments are dynamic
Treadmilling: net growth at one end, shortening at other end (both MT’s and MF’s)
Dynamic instability: switching between growing and shortening (only MT’s)

Question 27

cilia

Answer 27

hair like particle responsible for movement in wavelike motion, usually many per cell

Question 28

flagella

Answer 28

responsible for movement in propeller motion, usually only a couple per cell

Question 29

dyenin motors

Answer 29

move cilia and flagella
- attached permanently to microtubule
- use ATP as energy source
- move towards - end

Question 30

KInesin

Answer 30

another motor molecule
- walks along microtubules
- use ATP and myosin as energy
- move towards + end

Question 31

cell membranes
- integral protein
- peripheral protein

Answer 31

Phospholipid bilayer with cholesterol to control fluidity
Contains membrane proteins to regulate movement in / out of the cell
Integral protein: penetrates bilayer (channels, receptors)
Peripheral protein: anchors on bilayer surface

Question 32

Passive transport
- simple diffusion
- facilitated diffusion

Answer 32

Spontaneous, requires no energy
Materials move DOWN gradient (from area of higher to lower concentration)
Simple diffusion : move directly across membrane (ex: liquids, small uncharged molecules)
Facilitated diffusion: involves channel / carrier protein (large mcls, ions, polar molecules)
Gated process: opens / closes w ligand signal

Question 33

active transport
- 1o active transport
- 2o active transport (antiport / symport)

Answer 33

Requires E (ATP / ion gradient)
Moves against gradient using pump
1o active transport: directly uses ATP to pump molecule in or out
2o active transport: coupled transport using concentration gradient
Antiport: 2 solutes move in opposite directions
Symport: 2 solutes move in same direction

Question 35

endocytosis
- phagocytosis
- pinocytosis
- receptor mediated

Answer 35

Uptake items via vesicle formation
Phagocytosis: uptake of particles
Pinocytosis: uptake of fluids
Receptor mediated : uptake of specific item (ex: LDL uptake)

Question 36

LDL Uptake steps

Answer 36

LDL particle binds with coated pit
Clathrin vesicles form
Vesicles become uncoated
Vesicle fuses with lysosomes
Lysosomes digest LDL and release cholesterol

Question 37

protien trafficking

Answer 37

Ribosome attaches to ER with protein
Protein is inserted into ER during translation
Signal sequence is removed from protein
Vesicle transports protein to golgi (enters on cis face)
Protein is modified in golgi
Protein leaves golgi on trans face in transport vesicle
Protein is released from cell via exocytosis