lecture final Flashcards
7 questions from cell and its function
describe the plasma membrane
the nucleus is like ______
the cytoplasm is a jelly like substance that contains ______ between the ______ and nuclear membrane
its the door of the cell
- ampipathic bilayer
- made of phspholipids
- Blueprints
- organelles, cell membrane
what are the intracellular and extracellular ions?
intracellular:
K+, Mg2+, PO4, SO4, CHO3
extracellular:
Na, Cl, Ca2+
what are the 4 functions of the glycocalyx ?
1- cell binding
2- receptor for hormone binding
3- gives surface a negative charge (can repel neg. molecules)
4-assists immune reactions
what are the two ways to alter gene expression?
1- genetic-changes to DNA during transcription
2- epigenetic- changes in gene EXPRESSION
in epigenetics the dna is wrapped around _____ to prevent DNA from being transcribed
Histone
** addition of acetyl group unwraps and exposes DNA
the nuclear envelope is continous with ________.
the endoplasmic reticulum
what are the protein making “factories?”
ribosomes
Lysosomes aka suicide bags have 3 different classes, what are they?
- formed by golgi apparatus
- hydrolases
autophagy- recycling damaged cells
necrosis- uncontrolled cell death
apoptosis-controlled cell death
peroxisomes are similar to lysosomes but differ in 2 ways
1- self replication from smooth ER
2- oxidases
what is the powerhouse of the cell?
the mitochondria
- in cytoplasm
- self replicating
7 questions from transcription/ translation
nitrogen bases are attatched to DNA strands by ________ bonds.
hydrogen
what are the 4 steps in transcription with their enzymes?
1- unzip the genes- DNA helicase
2-initiation- RNA polymerase
3- elongation- creating mRNA
4-termination- RNA polymerase dissociates itself
what exactly is RNA?
its a ribonucleic acid, its single stranded and instead of Uracil it likes thymine
composed of exons
what is the process where exons are taken to the cytoplasm to be translated?
translocation
where does protein translation take place?
cytoplasm
6 questions molecular genetics/ cell div.
translation occurs in which direction?
5’ - 3’
amino acids are connected to one another by a _______ bond?
peptide
protein conformation and function is constantly modified by _______ state.
phosphorylation
what is the major excitatory neurotransmitter of the CNS?
Glutamate
what is the major inhibitory neurotransmitter of the CNS?
GABA
what happens in DNA replication (S-phase)?
MITOSIS
** the nucleus replicates its DNA and centrosomes
what are the steps of mitosis?
1- interphase (S phase) 2- prophase 3- prometaphase 4- metaphase- line up in the middle 5-anaphase- chromatids move to the poles 6- telophase- nuclear envelope forms
what are oncogenes?
genes that can lead to cancer
** supressed by antioncogenes
whats an example of a cancer caused by a virus?
HPV
7 questions from cell transport
what percent of the human body is composed of fluid?
60%
1/3 extracellular
2/3 intracellular
what is simple diffusion?
the continuous movment of molecules toward a decrease in free energy. often involves molecules traveling down their concentration gradiant
-does NOT require additional energy
what kind of hormones can travel freely across cellular membranes?
Steroid hormones because they are lipid soluable(non polar)
what do potassium ions flow through?
leaky channels because they are stripped of their hydration shell
what are the 2 sodium channels?
1- ligand gated- chemically gated
2- voltage gated
what carrier protein facilitates glucose diffusion into the cell?
GLUT4
** triggers membrane trafficking of GLUT4 to aid uptake
type 2 diabetes involves_______ ______.
insulin deficiency
what the hell is the nernst potential?
electromotive force- electrical properties of ions attracting and repelling one another
- when in equilibrium there is a resting membrane potential
what is Osmosis?
osmosis is simple diffusion of a solvent
or
the diffusion of water caused by a concentration difference of water
what is osmotic pressure?
the exact amount of pressure to stop osmosis…
think about a beer bong and making sure it doesnt spill before you drink
if cells are hypertonic the water is ______
if the cell is isotonic the water ______
if the cell is hypotonic water is ______
- leaving
- equilibrium
- coming in causing cells to burst
what is active transport?
cell membrane moving molecules against concentration gradient
primary- energy goes against gradient from ATP
-secondary- energy goes against gradient from another source
secondary active transport (symport) is when a molecule can ___________ off another molecules concentration gradiant
piggy back
** case of glucose and sodium
secondary active transport (antiport) molecules are shuttled in ______ directions in regaurds to concentration gradient.
opposite
what is endocytosis?
a process of cellular ingestionby which plasma folds bring substances into the cell
1- pinocytosis
2- receptor mediated endocytosis
3- phagocytosis
membrane and action potentials 10 questions
what can diffuse freely in either direction across the cell membrane?
K+
resting membrane potential values for most cells range from _____ to _____
-65 to -95 mV
resting membrane potential is predicted by what equation?
GHK
goldman hodgkin katz
what are 2 major forces acting on the movment of ions across the cell membrane/
1- charge
2- concentration gradient
the nernst equation measures ______
membrane potential
the GHK equation is used to determine ______
resting membrane potential when there is no net diffusion
action potentials are _____ or _____
all or none
the voltage gated Na+ channels inactivate quickly due to _____ and ______ mechanism
ball and chain
when the membrane potential is close to +30mV its called _______
overshoot
after overshoot there is a huge driving force for K+ to flow out and reestablish equilibrium potential called _______
repolarization
what are the refractory mechanisms (2) in place to keep cells from being over activated?
absolute refeactory period-channels will not open temporarily regardless of stimulus strength (like a flood gate)
relative refactory period-driving force leaving the cell is higher than to enter the cell
name the 3 connective tissues surrounding muscles
1- epimysium- covers whole muscle
2- perimysium- around bundles
3- endomysium- around each muscle fiber
what are the lines, bands and zones?
Z-line-protein filaments
I bands- only actin
A bands- all of myosin and some actin overlap
H zone- only myosin (disappears during contraction)
m-line- center of sacromere
what is a sliding filament mechanism?
process by which myosin heads form cross bridges with actin and contraction slides the 2 filaments past each other (the filaments do not actually shorten, they overlap)
what is the “walk along”/ ratchet theory of contraction?
the heads of myosin and actin swivel and slide past each other, called the power stroke, the myosin head then detatches and walks to next active binding site
what is the role of ATP in muscle contraction?
before contraction ATP binds to myosin heads, then ATPase cleaves a phosphate (hydrolysis)causing mysoin head to cock then energized myosin binds to actin; stored energy is released and then power stroke happens
myosin releases actin only when a new ATP binds to myosin
Ca2+ binds to troponin which moves tropomyosin and exposes myosin binding site to ______.
actin
*troponin is like a long sleve shirt, tropomyosin is like the shirt sleve getting pushed up, myosin is like skin
the relaxation phase is when the troponin lets the tropomyosin go, pulling shirt sleve back down and then _______ cannot bind
actin
what are some factors that affect contractile strength?
- number of muscle fibers
- frequency of stimulation
- thickness of each muscle fiber
- velocity of contraction
as load increases, the velocity of the contraction _______
decreases
maximal efficiency occurs at _____ of maximum muscle contraction velocity
30%
______ are important for absorbing high impact and keeping muscle fibers taught.
tendons
how do you judge the efficiency of a muscle contraction?
% of input ebergy that can be converted into work in muscle is less than 25%
in muscle contraction ATP is used for what?
1- walk along mechanism
2- active calcium pumps which send Ca into SR
3- Ma+/K+ pump in muscle fiber membranes
how do you tell Vo2 max?
once maxed out on o2 consumption while exercising, you have vo2 max
what are slow motor units (type 1)
fast fatigable motor units (type 2 B)
fast fatigue resistant (type 2 A)
myoglobbin, mitochrondria, capillary beds, resistant to fatigue, small force
fast fatigue- pale muscle fibers, large force, easily fatigued
fast fatigue resistant- intermediate motor units
as synaptic activity driving motor neurons increase, slow motor neurons are recruited ____. fast fatigue resistant _____ and fast fatigue _______
1st
2nd
last
what is hypertrophy? atrophy? and Hyperplasia?
hypertrophy- increase in total muscle mass in actin and myosin NOT muscle fibers
atrophy- decrease in total muscle mass
hyperplasia- increase in number of muscle fibers
endurance uses more _______
high intensity exercise uses more _______
- type 1
- type 2 B
what happens as we age?
decrease in type 2 fibers
- reduced density of capillaries
- decrease in neural excitation
smooth muscle- 3 questions
what are the 2 types of smooth muscle?
1- unitary/ single unit- MOST COMMON IN BODY, sheets/ bundles, contract as single unit
2- multi unit-individual fibers, contracts as individual units
smooth muscle has distinct microanatomy- tell me about it
not striated
- more actin than myosin
- longer thin filaments
- actin attatched to dense bodies
- side polar arrangment
