biology Flashcards
Matter
all the stuff around us
-substance that takes up space and has mass
Composed of:
-elements
Atom
smallest unit of matter
Molecule
when two or more atoms join together
Ribose
5 carbon sugar (CH2O)n where n=5
Fructose
6 carbon sugar (CH2On where n=6 and is an isomer of glucose
Glucose
6 carbon sugar (CH2O)N where n=6 and is an isomer of fructose
Dissacharides
2 monomers come together via dehydration rxn or condensation rxn
What connects carbohydrates together?
glycosidic bond
Sucrose
dissacharide
-1 glucose and 1 fructose
Lactose
dissacharide
-1 galactose and 1 glucose
Maltose
dissacharide
-2 glucose monomers linked togehter
Starch
Polysaccharide
- storage in plants
- glucose monomers linear and branched
Amylose
linear plant starch
-a-1,4 glycosidic bonds
Amylopectin
branched form of plant starch
-a-1,6 glycosidic bonds
Glycogen
Polysaccharide found in humans
- storage of glucose in humans
- more branching than in starch (amylopectin)
Cellulose
Structural polysaccharide in plant cell walls
- glucose polymer
- B-1,4 glycosidic bonds
Polypeptide
Polymers of amino acids connected by peptide bonds
-form via dehydration rxn to make peptide bonds
Secondary structure of protein
intermolecular interactions between atoms of poleypetid backbone
- does not involve R groups
- Hydrogen bonding N-H
Most commne secondary proteins:
b-pleated sheets
-alpha helices
Tertiary Structure
interaction between R groups at various Aino acids:
-interactions includse: ioninc bonding, hydrogen bonding, dipole dipole interactions and London dispersions
What can denature proteins?
excess temperature
chemicals
pH changes
radiation
Protein Function
1) Storage
- reserve of amino acids
2) Hormones
- signaling molecules that circulate through the body to regulate physiological processes
3) Motion
- Movement generation for individual cells or entire organism
4) Structure
- provide strength and support to tissues
5) Immunity
- prevention and protection against foreign invaders
6) Enzymes
Enzymes
biological, globular (usually) protein catalysts that speed up specific forward and reverse reactions by lowering activation energies
Enzymes specificity constant
measures how efficient an enzyme is converting a substrate to product
-High specificity constant=High substrate affinity=highly efficient enzyme
Ribozyme
RNA molecule capable of acting like an enzyme
Cofactors
nonprotein molecules
-assist enzymes in the reaction they manipulate
Coenzymes
Organic Coenzymes
-ex: vitamins
Inorganic Coenzymes
-metal ions such as Fe2+ or Mg2+
Holoenzymes
enzymes that are bound to their cofactor
Apoenzyme
enzyme not bound to cofactor
Competitive inhibition
inhibitors compete with substrates for active sites on enzymes
-increase substrate; higher chance substrate binds to active site(outcompete)
Km Increases
-Vmax remains the same
Noncompetitive inhibition
Inhibitors bind to allosteric site of enzymes
-modifies active site so that the substrate has reducing binding or can’t bind to active site at all
Km remains the same
Vmax Decreeases
Velocity (V) or reaction
-definition
rate at which the reaction is occuring
Vmax
-definition
Maximum velocity the reaction can go
Michaelis Constant (Km)
the susbtrate concentration at which the velocity is 50% of the Vmax
- small Km=high binding affinity, only need a little bit of substrate
- large Km=low binding affinity, need a lot of substrate
Polypeptides
polymers of amino acids
Lipids
Hydrophobic, non polar molecules
-long hydrocarbon chain
Lipids function
1) Store energy
2) Provide insulation
3) contribute to cell membranes
4) synthesis of critical hormones
Triacylglycerol/triacylglyceride
Lipid Molecule: Fat -found in cells call adipocytes composed of: glycerol backbone -3 FAtty acid tails
Phospholipids
found in cell membranes LIPID MOLECULE Composed of: -glycerol backbone -one phosphate group (Polar head group) -2 FA's
AMPHipathic molecule-contain hydrophobic and hydrophilic molecules
Amphipathic
contain hydrophobic and hydrophilic regions
Glycolipids
Found in cell membranes LIPID MOLECULE Composed of: glycerol backbone -carbohydrate (polar head grouP) -2FA's
Cholesterol
LIPID MOlecule
- make up 30-40% of eukaryotic cell membrane
- amphipathic
- 4 hydrocarbon rings=steroid nucleus
Liver makes cholesterol and also comes from our diet
What factors influence the fluidity of a membrane
1) temperature
2) cholesterol
3) degrees of unsaturation
Cold:
increases FA unsaturation
Function of cholesterol
1) Membrane fluidity
2) precursor for Vit D, Bile Acids,
3) Steroid Precursor
- testosterone and estrogen (sex hormones)
Why is RNA more reactive than DNA
RNA is more reactive (less stable) due to its 2’OH
Which nitrogenous bases bind to each other in DNA vs RNA and how many bonds between
DNA
A=T 2 H bonds
G-C 3 H bonds
RNA
A=U 2 H bonds
G-C 3 H bonds
Cell Theory
1) All life is composed of one or more cells
2) The cell is the basic structural, functional, and organizational unit of life
3) All cells come from preexisting cells via cell division
4) Division allows the genetic information within the cell to be passed onto new cells
5) organisms activity is dependent on the activity of its independent cells
6) Metabolism and biochemistry (energy Flow) occurs within the cells
7) All cells have the same chemical composition
**DOES NOT APPPLY TO VIRUSES BC THEY ARE NOT Living cells
Prions
misfolded proteins that cause other proteins to misfold
-destroy function
Cell Membrane
composed of:
1) Phospholipids
2) Cholesterol
3) Proteins
Membrane Proteins
Cell membrane
2 types:
1) Integral Proteins (Transmembrane proteins)
- extend through the entire phospholipid bilayr
- amphipathic
- Receptor proteins
2) Peripheral membrane Protein
- on the periphery
- hydrophilic
- can be attached to to the hydrophilic surface of integral membanre proteins or partially inserted into the membrane
Peripheral Membrane function
1) Adhesion Proteins
- attach adjacent cells to other things Iike other cells
- act as anchors for the cytoskeleton
2) Cellular regonition proteins:
- help cells recognize each other
- interact with receptor proteins
Simple Diffusion
- Flow of substances down their concentration gradient (High to Low concentration)
- usually small uncharged nonpolar particles such as Oxygen and CO2
- Does not require energy/consume energy
Osomosis a type of simple diffusion
Facilitated Transport
How large, hydrophilic molecules travel across the phospholipid bilayer through integral proteins
Can be:
- uniport-one molecule moving in one direction
- symport- several molecules moving in one direction
- antiport- several molecules moving in opposite direction
2 main types of integral proteins involved in facilitated transport
Channel Proteins
- Tunnels that face extracellular and intracellular environments
- small polar molecules and ions
Carrier proteins:
- change shape to facilitate movement of molecules through the protein
- only face one side at a time
Passive Diffusion
Type of Facliitate transport
- particles down their concentration gradient (high to low concentration)
- does not require eneergy
- relies on channel proteins (Tunnels)
Porins
example of channel proteins used in passive diffusion
Active Transport
particles travel against their concentration gradient (low to high concentration)
- require energy input
- energy source dictates if it will be primary or secondary active transport
- rely on carrier proteins that change their shape
Primary Active Transport
-used the energy released from ATP hydrolysis to pump molecules against their concentration gradient
Ex: Na+/K+ pump because it hydrloyzes ATP
Na+/K+ pump
exchanges:
-3 Na+ out and 2 K+ in; both go against concentration gradient by primary active transport
Pump consumes one ATP molecule
-ATP hydrolysis powers pump
-pump also an ATPase(ATP hydrolysis enzyme)
Secondary Active Transport
uses energy obtained form a source other than ATP
- usually free energy released by molecules traveling down their concentariotn gradient
- *relies on primary active transport to create concentration gradient
Cytosis
processes the cells use to facilitate bulk transport of large, hydrophilic/polar molecules
2 main types: -Endocytosis -exocytosis both require energy -both are active transport mechanism
Endocytosis
cell membrane forms a plasma membrane bound package (vacuole or vesicle) around something the extracellular matrix wants to internalize
-transports molecules into the cell
Phagocytosis
type of endocytosis
- cell engulfs undissolved materials
- known as cellular eating
Pinocytosis
type of endocytosis: similar to phagocytosis
- known as cellular drinking
- cell will pinch inward (INVAGINATE) so that it engulfs dissolved materials (liquids)
Exocytosis
when material exit the cell
-essential part of the vesicle secretion from the Golgi apparatus
Nucleus
In eukaryotic cells
- house and protect DNA
- DNA replication and Transcription occur inside the nucleus
Nuclear envelope
nucleus membrane
- set of 2 phospholipid bilayers (one inner and one outer)
- inbetween two bilayers=perinuclear space
Nucleoplasm
Aqueous medium in the nucleus
-DNA is floating in this
Nuclear pores
Holes In the nuclear envelope allowing for molecules to travel in and out
nuclear lamina
associated with the inner membrane of nuclear envelope
- Provides structural support to the nucleus
- regulates DNA organization, DNA replication, and Cell division
Nucleolus
dense regions within the nucleus
- where rRNA is produced
- site of ribosomal subunits production
Ribosomal subunits
contain rRNA and protein
composed in the nucleolus
Ribosomes
function in protein translation
- do not contain a membrane
- NOT organelles
- both eukaryotes and prokaryotes contain ribosomes
Float freely in the cytosol or attached to the RER
Eukaryotic Ribosomes
2 subunits:
60S subunit
40S subunit
come together to form the 80S eukaryotic ribosome*
-each subunit produced in the nucleoplasm and come together in the cytosol of the cell
RER
ribosomes attach to the cytoplasmic side and translate proteins in the lumen
- undergo modifications
- ex: glycolsylation attaches a carbohydrate to protein then the glycoprotein heads to the Golgi apparatus
role of the SER
synthesize lipids (fats), steroid hormones, detoxify cells
Golgi apparatus
Products enter golgi and undergo modifications such as phosphorylation
cytoskeleton
lies within the cytoplasm of both eukaryotic and prokaryotic cells
contains:
microfilaments
-intermediate filaments
-microtubules
Microfilaments
smallest diameter
- contain a double helix of 2 actin filaments
- crucial role in cell movement
Intermediate filament
middle diameter of the 3
- contain many different types of proteins
- EX: keratin-skin hair and nails
- primary role cellular structural support
Microtulbules
Provide structural integrity
- hollow tube, walls made up of tubular protein dimers
- partake in cell division and production of cilia and flagella
Tight Junctions
proteins juctnios that provide water tight seal b/w cells
-insure that materials must enter the cell to pass through the tissue
Ex; cell linings and digestive tract
Desmosomes
STAPLES that hole adjacent cells together
-provide mechanical stability and present in tissues subject to mechanical stress
Anchor juctions
Desmosomes and adhering suctions type of anchor juctnios
Gap junctions
allow for passage of small ions and small molecules between cells
-ie heart
Osmosis
simple diffusion mechanism (no energy and does not utilize channel proteins)
-water travels across a semipermeable membrane from areas of LOW TO HIGH SOLUTE CONCENTRATION (high to low water concentration)
Isotonic Solutions
extracellular and intracellular enviroments have the same solute concentration
-animal cells prefer
Hypertonic SOlution
solute concentration outside the cell is high
- water will leave the cell via osmosis to attempt to lower solute concentration
- LOSS OF FLUID causes the cell to shrivel
Cells in this solution undergo PLASMOLYSIS(shrinkage of cytoplasm from water loss away from cell wall)
Hypotonic Solution
If the solute concentration is lower outside the cell than inside the cell
- water from external environment will travel into cell
- animal cell will swell and eventually burst in a process called Cell lysis
Exergonic Reactions
release energy
Endergonic reactions
require energy
ATP
- unstable RNA nucleoside triphosphate
- ATP =hydrolysis reactions are exergonic (release energy) and spontaneous
- reaction coupling links unfavorable reactions with favorable ones
Mitochondria
powerhouse of the cell
-make ATP through cellular respiration (Catabolic process)
Endosymbioitic theory
aerobic bacteria were internalized as mitochondria whale photosynthetic bacteria became chloroplasts
-evidence=size similarities and mitochondria and chloroplast contain their own circular DNA and ribosomes
Glycolysis
converts 6C glucose into 3C pyruvate
- only pathway in aerobic glycolysis that does not require oxygen=aneorobic process
- occurs within the cytosol of the cell
- STEPs 1-5=energy investment phase
- STeps 6-10=energy payoff phase
4 ATP produced, 2 ATP invested= 2ATP net gain
Oxidation of Pyruvate in Mitochondria
1) Carboxyl group is removed from Pyruvate releasing CO2
2) NAD+ is reduced to NADH
3) acetyl group is transferred to coenzyme A=Acetyl CoA
Enzyme: Pyruvate Dehydrogenase complex
Krebs cycle: where does it occur in eukaryotes vs prokaryotes?
Eukarhotes=Mitochonrial matrix
Prokaryotes=Cytosol
What does the Krebs cycle produce?
2 CO2
3NADH
1FADH2
1 GTP
