Midterm 1 Flashcards
what is compartmentalization
required components of a metabolic pathway are concentrated in a confined space within the cell
what 4 things is the cell membrane composed of
phospholipids
cholesterol
proteins
carbohydrates
what types of molecules can move across the cell membrane without help and what are examples
Fat-soluble and small, uncharged molecules.
examples:
- O2
- H2
- CO2
- H2O
- glycerol
what types of molecules need help to move across the membrane and what are examples
water-soluble, large, uncharged and charged molecules.
examples:
- glucose
- sucrose
- ions
what does cholesterol do in the cell membrane
reduces cell membrane fluidity and permeability
what are the jobs of proteins in the cell membrane
junctions
enzymes
transport
recognition
anchorage
transduction
how much of the membrane do integral proteins span
partially or entire width.
entire width = transmembrane protein
what do peripheral proteins attach to
integral proteins or inner hydrophilic heads of phospholipids
what do carbohydrates attach to in the cell membrane
proteins/phospholipids
what are the functions of carbohydrates in the cell membrane
cushioning/protection
cell to cell recognition
binding
what is the inner layer of the nuclear envelope lined by and what is its function
lined by nuclear lamina.
organizes dna
what is the nucleoplasm and what does it contain
semi fluid matrix of nucleus.
chromatin: dna wrapped around histone proteins –> condense to form chromosomes.
nucleolus: site of rRNA synthesis and ribosome assembly
what does the cytoplasm contain
cytosol
cytoskeleton
organelles
what metabolic pathways is the cytosol the site for
glycolysis
gluconeogenesis
pentose phosphate pathway
fatty acid synthesis
what is the cytoskeleton composed of
fibrous proteins:
- actin filaments
- intermediate filaments
- microtubules
what is the function of the cytoskeleton
provide structure and support inside the cell.
anchors cell / aids in cell motility.
helps materials inside cell move
what are the nonmembranous organelles
ribosomes
centrosome/centrioles
cilia/flagella
cytoskeleton
nucleolus
what are the membranous organelles
2 lipid bilayer membrane:
- nucleus
- mitochondria
1 lipid bilayer membrane:
- rough and smooth ER
- golgi apparatus
- lysosomes
- peroxisomes
- plasma membrane
what is the function of the smooth er
lipid processing center.
converts fat-soluble toxins to water-soluble substances.
sequesters ca2+ from cytosol
what happens in the mitochondria
fatty acid oxidation.
krebs.
oxidative phosphorylation.
regulates apoptosis
what is the function of lysosomes
site of intracellular digestion.
contains enzymes that break down old cellular components/foreign particles.
acidic ph is about 5
what do peroxisomes help with
fatty acid oxidation.
neutralize free radicals.
myelin synthesis.
cholesterol synthesis
function of the extracellular matrix
provide cells with structural support.
anchors cells in place.
binds cells together, forming tissues
what do primary structure proteins undergo and form
undergo condensation reactions to form long chains –> create peptide bonds
secondary structure of proteins
hydrogen bonds between hydrogen of amine group and oxygen of carbonyl group in polypeptides backbone.
alpha helix or beta sheets.
tertiary structure of proteins
interactions between R chains.
- hydrogen bonds
- ionic bonds
- van der waals interactions
- hydrophobic interactions
- disulfide bridges
3D shape
quaternary structure of proteins
interactions between multiple polypeptide chains
components of fibrous / globular
fibrous: elongated, insoluble in water, structural.
- ex: collagen/elastin
globular: compact/spherical, soluble exterior with insoluble interior, non-structural roles.
- ex: immunoglobin, hemoglobin, enzymes
explain the general structure of carbohydrates
chains of carbons with hydroxyl groups and one carbonyl group.
terminal = aldose.
non-terminal = ketose.
D or L based on location of hydroxyl furthest from carbonyl
do aldehydes or ketones have a higher priority? how do you name them?
aldehydes have higher priority.
name as aldehyde and ketone is “oxo” substituent
what do condensation reactions form
glycosidic bonds –> create disaccharides / oligosaccharides / polysaccharides.
forms between hydroxyl of one group and anomeric carbon of another
what is an anomeric carbon
in a cyclic carbon, the carbon that was the carbonyl carbon in acyclic form.
next to the oxygen atom in the ring
what is sucrose
glucose
fructose
what is maltose
glucose
glucose
what is lactose
glucose
galactose
what are oligosaccharides typically bound to and what are examples
bound to proteins in membrane as glycoproteins.
ex: immunoglobulin, mucin.
examples of polysaccharides
cellulose
starch
GAGs
glycogen
what bonds does cellulose have? branching or no branching?
beta bonds, no branching
can cellulose be digested by humans?
unable to be digested by humans
what does cellulose do in the digestive tract
helps delay absorption of other carbs in your digestive tract, thereby preventing blood glucose spikes
what is starch
storage form of glucose in plants
what types of bonds does starch have? branching or no branching?
alpha bonds.
branched or unbranched.
- branched: amylopectin
- unbranched: amylose
what is glycogen
storage form of glucose in animals.
created if the body has enough glucose for energy needs.
live and muscle
what type of bonds does glycogen have? branching or unbranching?
alpha bonds.
extensive branching.
what are GAGs composed of
repeating disaccharide units (amino sugar and uronic acid or galactose)
are GAGs branched or unbranched
branched.
bottle brush structure.
do GAGs have a positive or negative charge
negative charge - attracts water.
lubricant/shock absorber due to high viscosity, low compressibility
where are GAGs located
ECM or cell membranes.
fill ECM as hydrated gel
what are proteoglycans
GAGs that are attached to core proteins
what are the 5 groups of GAGs
- Chondroitin sulfate (most abundant).
- Keratan sulfate (originally isolated in cornea).
- Dermatan sulfate (mostly found in skin).
- Heparan sulfate (animal tissues).
- Hyaluronate (only GAG not sulfated or linked to a core protein; vitreous humor).
examples of GAGs
Aggrecan
Lumican
Keratocan
Mimecan
Decorin
what are lipids and what do they consist of
organic compounds.
largely hydrophobic.
consists mainly of carbon and hydrogen, some oxygen.
what are the types of simple lipids
esters of fatty acids:
- fatty acids
- triglycerides
what is the precursor to triglycerides
fatty acids
what is palmitic acid
hexadecanoic acid.
fatty acid.
most common saturated fat in plants and animals.
what does omega refer to
the position of the 1st double bond relative to the methyl end (omega end)
what type of bond do saturated fatty acids have
single bonds
what type of bond do unsaturated fatty acids have
double bonds:
- cis: naturally occurring
- trans: processed fats
structure of triglyceride
glycerol as the alcohol ester with fatty acids
function of triglycerides
energy store
thermal insulation
filling space
binding organs together
cushioning organs
when are triglycerides broken down
during low food periods for energy
structure of complex lipids and the types
esters of fatty acids + additional groups.
phospholipids.
sphingolipids.
function of phospholipids
structural component of cell/organelle membranes.
aid in fat digestion
structure of phospholipids
2 fatty acids + glycerol + phosphate + 1 polar group.
possible polar groups:
- ethanolamine
- choline = phospholipid
- serine
- inositol
function of sphingolipids
structural component of cell membranes (esp. nerve cells)
chemical messengers
structure of sphingolipids
sphinogosine as the alcohol ester with fatty acids + head group.
possible head group:
- hydrogen (ceramide).
- phosphocholine (sphingomyelin).
- sugar (glycolipid; 1 sugar = cerebroside, >1 sugar =ganglioside).
what are derived lipids derived from and name the different types
hydrolysis of simple/complex lipids.
steroids.
fat-soluble vitamins.
eicosanoids.
isoprenoids.
structure of steroids
4 fused rings with unique side chainssi
side chain of sterols
hydroxyl
most common sterol
cholesterol
what is cholesterol a precursor to
steroid hormones and bile salts
what are steroid hormones and the different types
chemical messengers.
mineralocorticoids: corticosterone, aldosterone.
glucocorticoids: cortisol.
sex steroids: progesterone, testosterone, estrogen.
vitamin d: some true steroid characteristics
what are bile salts
acid conjugated with glycine or taurine - reaction produces water and chemical salts
where are bile salts stored
gallbladder
function of bile salts
digestion of dietary lipids
absorption of fat-soluble vitamins A, D, E, K
what are the fat-soluble vitamins
A
D
E
K
what are fat-soluble vitamins involved in
blood clotting
wound healing
vision
calcium absorption
what are eicosanoids and what are they derived from
chemical messengers.
derived from arachidonic acid
examples of eicosanoids
prostaglandins
leukotrienes
thromboxanes
what are isoprenoids
isoprene subunits of unsaturated pentahydrocarbons.
fat soluble vitamins A, E, and K
what are minerals
inorganics found in soil / water and absorbed by plants, eaten by animals
macromolecules and their functions
- Calcium:
- bone and teeth formation
- muscle contraction
- nervous system function
- hormone secretion - Phosphorus:
- ATP formation
- bone formation
- hormone activation - Chloride:
- nervous system function
- fluid balance - Potassium:
- nervous system function
- fluid balance
- blood pressure regulation - Sodium:
- nervous system function
- fluid balance
- blood pressure regulation
- muscle contraction - Magnesium
what are the microminerals and their functions
- Selenium: antioxidant.
- Copper: antioxidant.
- Zinc: antioxidant.
- Iodine: thyroid hormone production.
- Chromium
- Iron: hemoglobin formation
what are vitamins
organics made by plants and animals, eaten by humans
what vitamins does the body not make enough of
vitamin d and k
what do most vitamins function as
coenzymes: organic molecules that are required by certain enzymes to carry out catalysis
what are the fat-soluble vitamins and their functions
- A - retinol: vision; deficiency: night blindness, dry eye.
- D - cholecalciferol.
- E - tocopherol: antioxidant.
- K: blood clotting; deficiency: hemorrhage.
what are the water-soluble vitamins and their functions
B1 - Thiamine.
B2 - Riboflavin: corneal cross linking.
B3 - Niacin.
B5 - Pantothenoic acid.
B6 - Pyridoxine.
B7 - Biotin.
B9 - Folate/folic acid.
B12 - Cobalamin: myelin synthesis, RBC formation; deficiency: irreversible nerve damage, anemia.
C - Ascorbic acid: antioxidant.
how are electronegativity and atomic size related on the periodic table
inversely related.
electronegativity is greatest in top right corner.
atomic size is greatest in bottom left corner.
what do polar covalent bonds create
partial negatives and positives.
cations: pos. charge, loss of electrons.
anions: neg. charge, gain of electrons.
nonpolar molecules are not electrostatically attracted to water, so water forms ordered cages around them.
what does the value of pKa change with
temperature
what is Ka
dissociation or equilibrium constant.
a stronger acid dissociates completely and will have a large [H+], therefore a large Ka.
what do weak acids neutralize
OH
what do weak bases neutralize
H
what are phosphate buffers
phosphate exists as sodium dihydrogen phosphate (weak acid) and sodium monohydrogen phosphate (conjugate base)
what is carbonic acid / bicarbonate
carbonic acid: weak acid.
bicarbonate: conjugate base
what is the pH of blood
7.4
pH of blood = < 7.35
metabolic acidosis
pH of blood = > 7.45
metabolic alkalosis
do carboxyl functional groups act as weak acids or bases
weak acids
do amino functional groups act as weak acids or basese
weak bases
