chap. 2 Flashcards
macromolecule sizes (smallest to biggest)
1) monomer
2) dimer (2 monomers)
3) oligomer (3-10 monomers)
4) polymer (11+ monomers)
Dehydration synthesis
- binds a monomer to another macromolecule
- one macromolecule loses an H atom, and the other loses an OH, the two bind together and produce a water molecule as a product
hydrolysis
adding water breaks bonds between monomers
what are the four types of macromolecules
carbohydrates, lipids, proteins, nucleic acids
functional groups
small groups of atoms that give properties/functions to the macromolecule
carboxyl groups make compounds…
make compound weak acids
amino groups make compounds…
make compounds weak bases
carbohydrates
AKA sugars
- carbon chain with 2 H for every 1 O
- near immediate energy use & short to medium term energy storage
carbohydrate sizes
monomers: monosaccharides
dimers: disaccharides
oligomers: oligosaccharides
polymers: polysaccharides
Lipids
AKA fats
- lots of C and H, few O
types of lipids and their functions
fatty acids: long term energy storage (monomer name)
phospholipids: form cell membrane
steroids: hormone (signaling membranes)
Nucleic Acids
composed of nucleotides
- store genetic informations
- immediate energy use
- includes DNA and RNA
ATP
- adenosine triphosphate
- nucleotide
- immediate energy release in cells
- breaking bonds of ATP = energy release
- body uses 88lbs of ATP per day
Nucleotide
- monomer of nucleic acids
- made of a nitrogenous base, 5-carbon sugar (ribose or deoxyribose), and a phosphate group(s)
more phosphates = more energy
example: ATP
Proteins
AKA polypeptides
- composed of amino acids
functions: structure, cell signaling, movement, protection, catalysis, etc
amino acids
monomer of proteins
made of a central carbon, amino group (NH2) which is a weak base, a carboxyl group (COOH) which is a weak acid, and a functional group (R-group) which determines the amino acid’s name and function
how are amino acids bound together?
polypeptide chains (aka peptide bonds)
how are peptide bonds formed
formed by dehydration synthesis reaction of COOH and NH2 group of respective amino acids
primary protein structure
sequence of amino acids, determines all other levels of structure
secondary protein structure
partial-folded structures
containing Alpha helices and Beta pleated sheets
caused by hydrogen bonds between amino acids
tertiary protein structure
- 3D shape
- shape determine the protein function
- caused by interactions between R groups
conformation change
a change in protein function
- can be caused by different molecules binding, unbinding
- some proteins only function correctly when they undergo conformational changes regularly
denaturation
if a protein unfolds, losing its tertiary structure due to heat or acid exposure, it loses its function
denaturation is permeant
Quaternary Protein Structure
combination of two different polypeptides
caused by interactions between two polypeptides
enzymes
- a class of protein
- make reactions happen faster
- very powerful and have lots of energy
- lower activation energy: initial energy needed for a chemical reaction to occur
how enzymes work
enzymes have 3D activation sites that binds to a specific substrate
when they bind it creates a “enzyme-substrate complex”. They are not chemically bonded, just stuck together
when the product is created in can not stay attached
Cell size
cells are small because they need a high surface area to volume ration
the bigger a cell gets the smaller that ratio becomes
phospholipids
- forms 79% of the plasm membrane
- hydrophilic heads on either side and hydrophobic tails on the inside (makes a bilayer)
glycolipids
a subtype of phospholipids but with a carbohydrate attachment
hydrophilic head
love water
polar
made of glycerol and phosphate
hydrophobic tail
hates water
non-polar
made of 2 fatty acids
cholesterol
spread out among the phospholipids making up about 19% of the membrane
affects membrane fluidity (everything is constantly moving in the membrane)
low cholesterol = stiff
high cholesterol = fluid
plasma membrane proteins
- proteins embedded between phospholipids (making up 2% of the membrane)
- there are many types and functions
- include glycoproteins
glycocalyx
- carbohydrates extending off cell membrane
- formed by glycoproteins and glycolipids
- provides protection and identification (like a name tag)
- if a cell shows up with the wrong glycocalyx, the immune system will get rid of it
type of plasma membrane proteins
receptors, channel proteins, and carrier proteins
receptor proteins
- binds to ligands
- allows cellular communication/signaling
- when a ligand binds, leads to the release if many other (secondary) messenger molecules inside the cell, greatly increasing the effect
ligands
any chemical used for signaling/communication
channel proteins
proteins with a passage allowing smaller molecules in/out of the cell
Passive transport
two types: leak channels (always open), and gated channels
gated channels
can be opened or closed by a stimulus
3 types: ligand gated, voltage gated, and mechanical gated
ligand-gated
opened/closed when the bind to a ligand
voltage-gated
open/closed when charge across membrane changes
mechanical-gated
open/close due to physical forces
carrier protein
transport proteins that CARRY smaller molecules across plasma membrane
how it works:
1) molecule binds to site within carrier
2) carrier protein changes conformation (its tertiary structure)
3) molecule is released to other side of membrane
pumps
carrier proteins that require ATP to move molecules up gradient
primary active transport
sodium-potassium pump
pumps out 3 Na+ and pumps in 2 K+
types of pumps
uniporters: move one type of molecule
co-transporter: move two types of molecules
- symporters: move 2 molecules same direction
- antiporters: move 2 molecules in opposite directions
why are cell membranes semipermeable
so cells can maintain homeostasis
- permeable to nutrients and wastes
- impermeable to proteins and many charged ions
types of membrane transport
passive: simple diffusion, facilitated diffusion, and osmosis
active: primary and secondary active transport
simple diffusion
- movement of molecules directly through phospholipids (no proteins needed)
- lipids and gasses can pass directly through phospholipid bilayer
facilitated diffusion
movement of molecules down their gradient using carrier proteins or channel proteins
- ions, polar, water, etc. need to use a protein
osmosis tonicity
the ability for a solution to affect the water volume of a cell
osmosis
water moves from an area of low solute (high water) concentration to an area of high solute (low water) concentration through aquaporin channel proteins
water wants to go where there is LESS water (high solute)
hypotonic solution
has lower solution concentration than intercellular fluid
water enters cell
hypertonic solution
has greater solution concentration than intercellular fluid
water leaves cell
isotonic solution
has equal solute concentration as intercellular fluid
no net fluid movement
active transport
membrane transport requiring carrier proteins and energy from ATP
moves molecules up their gradient
primary active transport
movement of molecules using ATP directly
secondary active transport
movement of molecules using energy from ATP indirectly
done by co-transporters
molecule A moves down its concentration gradient, powering the movement of molecule B up its concentration gradient
molecule A’s concentration gradient is created by a primary active transporter
SGLT
- type of secondary active transport
- moves sodium and glucose into the cell
- sodium moves down concentration gradient, and glucose moves up
- sodium has a concentration gradient because the Na-K Pump uses ATP to pump it out of the cell
