AP Biology

carbohydrates

made of C,H,O, C:O ratio is 1:1, general formula is CH₂O

lipids

made of C,H,O, no general formula, C:O ratio is very high in C

proteins

molecular tools of the cell, made of C,H,O,N, and sometimes S, no general formula, polypeptide chain of Amino Acids linked by peptide bonds

nucleic acids

informational polymers, made of C,H,O,N, and P, polymers of nucleotides

ex. DNA and RNA

what do living systems depend on?

the properties of water (resulting from polarity and hydrogen bonding)

hydrogen bonds between water molecules

result in cohesion, adhesion, and surface tension

why must organisms exchange matter with the environment?

to grow, reproduce, and maintain organization

why are atoms and molecules from the environment necessary?

to build new molecules

carbon

used in storage compounds and cell formation in all organisms

phosphorus

used to build nucleic acids and certain lipids

what are hydrolysis and dehydration synthesis used for?

to cleave and form covalent bonds between monomers

what is biological information encoded in?

nucleotide monomers

nucleotide structure

a five-carbon sugar, a phosphate, and a nitrogenous base

R groups

categorized by chemical properties (hydrophobic, hydrophilic, or ionic)

what do interactions of R groups do?

determine structure and function of that region of protein

complex carbohydrates

comprised of sugar monomers

differences in saturation

determine the structure and function of lipids

phospholipids

contain polar regions that interact with other polar molecules

non-polar regions are often hydrophobic

linear sequence of nucleotides ends

3’ hydroxyl and 5’ phosphates

during DNA and RNA synthesis

nucleotides are added to the 3’ end

adenine pairs with

thymine (2 hydrogen bonds)

cytosine pairs with

guanine (3 hydrogen bonds)

four elements of protein structure

primary, secondary, tertiary, quaternary

what do carbohydrates comprise?

linear chains of sugar monomers connected by covalent bonds, may be linear or branched

structure

function

ribosomes

comprise ribosomal RNA and protein, they synthesize protein according to the mRNA sequence

found in all forms of life

rough ER

compartmentalizes the cell

smooth ER

detoxification and lipid synthesis

golgi apparatus

correct folding and chemical modification of newly synthesized proteins and packaging for protein trafficking

mitochondria

double membrane

outer membrane is smooth and inner membrane is highly convoluted

lysosome

membrane-enclosed sacs that contain hydrolytic enzymes

vacuole

membrane-bound sac that play many different roles

chloroplasts

specialized organelles that are found in photosynthetic algae and plants

have a double outer membrane

mitochondrial double membrane

provides compartments for different metabolic reactions

lysosome function

intracellular digestion, the recycling of a cell’s organic materials, and programmed cell death

vacuole function

storage and release of macromolecules and cellular waste products

chloroplast structure

thylakoids and the stroma

thylakoids

organized in stacks, called grana

membranes

contain chlorophyll pigments and electron electron transport proteins that comprise the photosystems

stroma

the fluid within the inner chloroplast membrane and outside the thylakoid

suface area to volume rations

affect the ability of a biological system to obtain necessary resources

why must the surface area of the plasma membrane be large?

adequately exchange materials

embedded proteins

can be hydrophobic with charged and polar side groups, or can be hydrophobic with nonpolar side groups

what does the structure of cell membranes result in?

selective permeability

what do cell membrane separate?

the internal environment of the cell from the external environment

fluid mosaic model

describes the structure of the plasma membrane as a mosaic of components, including phospholipids, cholesterol, proteins, and carbohydrates

polar uncharged molecules

pass through the membrane in small amounts

cell walls

provide a structural boundary, composed of complex carbohydrates

passive transport

the net movement of molecules from high concentration to low concentration without the direct input of metabolic energy

active transport

requires the direct input of energy to move molecules from regions of low concentration to regions of high concentration

exocytosis

internal vesicles fuse with the plasma membrane and secrete large molecules out of the cell

endocytosis

the cells take in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane

what do large quantities of water pass through?

aquaporins

charged ions

require channel proteins to move through the membrane

metabolic energy (atp)

required for active transport

isotonic

the cell is at equilibrium with the solute concentration outside the cell

hypertonic

when solute concentration is more inside the cell than outside so solute flows out of the cell

hypotonic

when solute concentration is less inside the cell than outside so solute flows into the cell

prokaryotes

generally lack internal membrane-bound organelles

eukaryotic cells

maintain internal membranes that partition the cell into specialized regions

how did membrane-bound organelles evolve from?

previously free-living prokaryotic cells via endosymbiosis

structure of enzymes

the active site that specifically interacts with substrate molecules

for an enzyme-mediated chemical reaction to occur

the shape and charge of the substrate must be compatible with the active site of the enzyme

enzymes

biological catalysts that lower the activation energy

denaturation of an enzyme

occurs when protein structure is disrupted

environmental temperatures and pH outside optimal range

will change its structure, altering efficiency to catalyze reactions

higher environmental temperatures

increase the speed of movements of molecules in a solution

competitive inhibitors

bind reversibly or irreversibly to the active site of the enzyme

noncompetitive inhibitors

bind to allosteric sites, changing the active site of the enzyme

all living systems require

constant input of energy

energy input

must exceed energy loss to maintain order and to power cellular processes

loss of order or energy flow

results in death

where did photosynthesis first evolve?

prokaryotic organisms

prokaryotic photosynthetic pathways

the foundation of eukaryotic photosynthesis

chlorophylls

absorb energy from light, boosting electrons to a higher energy level in photosystems I and II

photosystems I and II

embedded in the internal membranes of chloroplasts

calvin cycle

occurs in the stroma of the chloroplast

ETC

transfers energy from electrons in a series of coupled reactions that establish an electrochemical gradient across membranes

reactions occur in the chloroplast, mitochondria, and prokaryotic plasma membranes

krebs cycle

carbon dioxide is released from organic intermediates, ATP is synthesized from ADP and inorganic phosphate, electrons are transferred to coenzymes NADH and FADH2

ATP to ADP

releases energy, which powers many metabolic processes

both DNA and RNA

contain sugar, a phosphate group, and a nitrogenous base

DNA

contains deoxyribose and thymine, double stranded (anti parallel)

RNA

contains ribose and uracil, single stranded

what is DNA the primary source of?

heritable information

how is genetic information stored and passed to subsequent generations?

DNA or RNA molecules

adenine sometimes pairs with

uracil instead of thymine

purines (G and A)

double ring structure

pyrimidines (C, T and U)

single ring structure

what direction is DNA synthesized in?

5’ to 3’

replication

semi conservative process

one strand of DNA serves as the template for a new strand of complementary DNA

helicase

unwinds the DNA strands

topoisomerase

relaxes supercoiling in front of the replication fork

DNA polymerase

requires RNA primers to initiate DNA synthesis

synthesizes new DNA continuously on the leading strand and discontinuously on the lagging strand

ligase

joins the fragments on the lagging strand

mRNA molecules

carry information from DNA to the ribosome

tRNA molecules

bind to specific amino acids and have anti-codon sequences that base pair with mRNA

rRNA molecules

functional building blocks of ribosomes

noncoding strand

the DNA strand acting as the template strand

DNA is read

3’ to 5’

splicing

cutting out and rearranging sections of mRNA