Eukaryotic Cells

Question 1

3 principles of cell theory

Answer 1

all living organisms composed of 1 or more cells
cell is the most basic unit of life
all cells arise from preexisting living cells

Question 2

major differences between prokaryotes and eukaryotes

Answer 2

pro - no membrane boudn organelles, no histones, no post transcription modification of mrna , smaller ribosomes, pertidoglycan cells walls, binary fission
euk - mitosis, cells walls of chitin or cellulose if present

Question 3

difference between prokaryote and eukaryotic flagella

Answer 3

pro - made of flagellin and rotate around

euk - 9+2 microtubule configuration and have a whip like action

Question 4

describe the structure of the nucleus

Answer 4

outer nuclear envelope has pores that RNA (not dna!!!!) can exit
nucleolus is where rRNA is transcribed

Question 5

where would you expect to find lots of mitochondria

Answer 5

muscles where energy is required because it generates most of the cells atp via aerobic respiration

Question 6

how do mitochondria replicate

Answer 6

have their own circular dna and ribosomes

Question 7

where would you expect to find lysosomes

Answer 7

in cells that are about to undergo apoptosis because they break down macromolecules with hydrolytic enzymes

Question 8

what are peroxisomes

Answer 8

self replicatign cytosolic vesicles involved in lipid and protein storage
produce hydrogen peroxide to inactivate toxic substances

Question 9

what does the rough ER do

Answer 9

has a bunch of protein manufacturing ribosomes

once to proteins are made they will be sent to to the golgi and then the final destination outside of the cell

Question 10

some functions of the smooth ER

Answer 10

lipid and steroid catabolism and metabolism
carb metabolism
drug detox

Question 11

what does golgi apparatus do

Answer 11

processes and packages macromolecules

Question 12

where would you expect to find lots of golgi and rough ER

Answer 12

secretion cells like pituitary cells

Question 13

5 membrane bound organelles you must know

Answer 13

nucleus - contains dna 
mitochondria - produce energy
lysosomes - digest
ER rough - protein translation 
ER smooth - protein metabolism 
golgi - packaging

Question 14

what are the 3 structures in cytoskeleton small to largest

Answer 14

microfilaments (actin) – intermediate filament – microtubule

Question 15

microfilaments are used for

Answer 15

cytokinesis

work with myosin during muscle contraction

Question 16

what are microtubules used for

Answer 16

intracellular transport
cilia and flagella
mitotic spindle in mitosis and meiosis

Question 17

the cellular structures of a mitotic spindle

Answer 17

pair of centrioles in the centrosome (microtubule organizing center) has growing polar microtubles as they get closer to the chromosome becomes kinetochore microtubules. the point it attaches to the chromosome is the kinetochore

Question 18

how does cholesterol modulate membrane fluidity

Answer 18

at low temps prevents solidification by disrupting close packing of phospholipids
at high temps reduces phospholipid movement

Question 19

macromolecules permeability in regards to plasma membrane

Answer 19

if large too big to cross

Question 20

gases permeability in plasma membrane

Answer 20

small non polar = cross

Question 21

hydrophobic molecules permeability in plasma membran

Answer 21

can cross if small due to hydrophobic interior

Question 22

polar molecules permeability in plasma membrane

Answer 22

large - cant cross

small - hard to cross bc of polarity

Question 23

amino acids and charged ions permeability in plasma membrane

Answer 23

charged = cant cross

Question 24

3 types of endocytosis done by the plasma membrane

Answer 24

phagocytosis - eat the particle
pinocytosis - drink the particle
receptor mediated - has to bind to receptor

Question 25

how does exocytosis occur

Answer 25

golgi apparatus produces secretory vesicles

Question 26

difference between tight junction, desmosomes, gap junction

Answer 26

tight - water tight seal between cells prevents passage of molecules
desmosome - attach to cytoskeleton of each cell but dont prevent fluid from circulating
gap - tunnels connecting cells crucial for communication

Question 27

what can pass through a semi permeable membrane for the purposes of the mcat

Answer 27

small
non polar
lipid soluble
water

Question 28

describe passive diffusion

Answer 28

no energy
NON MEMBRANE PROTEINS
allows passage of permeable molecules down their concentration gradient

Question 29

what is facilitated diffusion

Answer 29

still no energy but there is a carrier protein so impermeable solutes can pass through based on their concentration gradient

Question 30

what is primary active transport

Answer 30

impermeable solute moved against concentration gradient where ATP is used directly to transport the solute in question

Question 31

explain the NA K pump ***

Answer 31

Na binds to protein
ATP phosphorylation changes protein conformation
expels 3 Na to extracellular fluid , K binds
K binding releases phosphate group which restores protein conformation
2 K released in cytoplasm

Question 32

what is secondary active transport

Answer 32

electrochemical gradient of one solute drives the transport of another molecule against its concentration gradient

Question 33

3 classes of membrane receptors (proteins that allow cells to communicate with environment)

Answer 33

enzyme linked
ligand gated ion channel
g protein coupled receptors

Question 34

explain cell signalling

Answer 34

plasma membrane has receptor proteins that are activated by a signal molecule trigger an internal cell signalling pathway mediated by secondary messengers where the signal becomes amplified and results in a cellular response

Question 35

what is the extracellular matrix

Answer 35

extracellular part of animal tissue that provides structural support to cells
has adhesive proteins which help cells stick together