AP Bio Midterm

what do all living cells contain?

genome and ribosomes

function of ribosomes

synthesize proteins according to mRNA sequences

ribosome structure

two subunits of rRNA and proteins

endoplasmic reticulum

network of membrane tubes within cytoplasm

rough er

* ribosomes attached to membrane
* compartmentalizes the cell
* associated with packing newly synthesized proteins for possible export

smooth er

* no ribosomes
* detoxification and lipid synthesis

golgi complex

* eukaryotic cells
* prepares newly synthesized proteins and packaging for protein transport

mitochondria

* double membrane
* produces ATP

lysosome

* contains hydrolytic enzymes
* can be used to digest materials including damaged cell parts or macromolecules
* program cell death

vacuoles

* membrane bound sacs
* variety of roles
* storage of water and macromolecules
* release of waste

chloroplasts

* double outer membrane
* captures energy from sun
* produces sugar for the organism
* photosynthesis

choloroplast structure

2 compartments

* thylakoid
* where light dependent reactions occur
* folded membrane compartments
* stroma
* fluid between membrane and thylakoids
* carbon fixation reactions occur here

mitochondria structure

* matrix
* where krebs cycle reactions occur
* inner membrane
* where electron transport and ATP synthesis occur
* highly folded

cell size and why

cells are typically small, moving materials increases in difficulty as a cell increases in size

surface area to volume ratio of a cell

smaller cells have a higher surface are to volume ratio

increase in volume…

causes a decrease in surface area and an increase for the demand for internal resources

cell membrane

* allows cell to establish an internal environment
* provides boundary between interior of cell and exterior
* controls transport in and out
* made of phospholipids
* have a polar and nonpolar head

peripheral proteins

* loosely bound to membrane surface
* hydrophilic with charged and polar side groups

integral proteins

* span membrane
* hydrophilic with charged and polar side groups
* hydrophobic with nonpolar side groups

membrane protein functions

* transport
* cell-cell recognition
* enzymatic activity
* signal transduction
* intercellular joining
* attachment for extracellular matrix or cytoskeleton

carbohydrates

* glycoproteins
* one or more carbohydrates attached to membrane protein
* glycolipids
* lipid with one or more carbohydrate attached

selectively permeable

small, nonpolar molecules pass freely

large, polar molecules and ions cannot pass freely

transport protein

channel protein

* allows specific target molecules to pass

carrier protein

* changes shape to move target molecule across sides

concentration graident

* separated by membrane
* high to low concentration

passive transport

no energy needed

diffusion

pass freely

facilitated diffusion

transport proteins

active transport

requires energy to move from low to high

endocytosis

cell uses energy to take in macromolecules and particulate matter by forming new vesicles

exocytosis

internal vesicles use energy to fuse with plasma membrane and secret large macromolecules out of the cell

osmosis

diffusion of water across a selectively permeable membrane

osmolarity

total solute concentration

hypertonic

more solute, less solvant

hypotonic

less solute, more solvant

water and solute concentration

water moves into the area with a higher solute concentration

water potential

tendency of water to move by osmosis(high to low potential)

role of enzymes

speed up biochemical reactions by lowering activation energy requirements

enzyme structure related to function

structural characteristics make it reaction specific

substrate/enzyme interaction

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

activation energy

initial starting energy required for a reaction to occur

denaturation

catalytic ability is lost or decreased

optimum temperature

range in which enzyme reactions occur fastest

pH

measure of hydrogen ion concentration

competitive inhibitor

binds to active site

can be reversable or irreversable