AP BIO UNIT 4 (cell stuff)

cytology

the study of cell structure

Robert hooke

first observed cell walls of oak bark in 1665

Antoni van leeuwenhoek

first observed living cells in 1674

light microscope

uses visible light and glass lens to magnify specimens

electron microscope

beam of electrons used to study cell structures, can’t be used to observe living cells

scanning electron microscope (SEM)

shows detailed surface topography of an organism

transmission electron microscope (TEM)

shows interior structure of a cell

cell fractionation

breaking cells apart and separating their components by spinning them

3 aspects of cell theory

• cells are the basic unit of structure and function

• ll living things are made of one or more cells

• all cells come from preexisting cells

prokaryotic cell

cell w/o membrane enclosed nucleus

eukaryotic cells

cell w/ membrane enclosed nucleus and organelles

prokaryotic organisms (2)

• bacteria

• archaea

eukaryotic organisms (4)

• protists

• fungi

• animals

• plants

nucleoid

region in a prokaryotic cell where DNA is concentrated, but not enclosed in a membrane

cytosol

the jelly-like substance inside a cell

chromosomes

structures containing DNA. and genetic info

ribosomes

complexes of rRNA + proteins that synthesize proteins

plasma membrane

selectively permeable Barrier surrounding a cell

surface area to volume ratio/why cells are small

smaller cells —> greater ratio—> things are more easily absorbed/moved (more efficient exchange of materials)—> why cells are so small

larger organism = larger cells ?

no, they have more cells not larger cells

nucleus

organelle that houses eukaryotic cell genes

nuclear envelope

double membrane surrounding the nucleus

chromatin

uncoiled DNA wrapped around histone proteins

histones

proteins around which DNA are wrapped

nucleolus

region where rRNA is made and ribosomal subunits are assembled

ribosomes

non-membrane bound structures that carry out protein synthesis

free ribosomes

ribosomes suspended in the cytosol that usually makes proteins functional inside the cell

bound ribosomes

ribosomes attached to the rough ER or nuclear envelope that make proteins used for secretion

endomembrane system (7)

• nuclear envelope

• ER

• Golgi

• lysosomes

• vesicles

• vacuoles

• plasma membrane

rough ER

ER covered in ribosomes

makes proteins usually used for secretion

smooth ER (4)

• lipid synthesis

• carb metabolism

• detox of drugs + poisons

• calcium storrage

glycoproteins

proteins w/ carbs attached

Golgi

modifies, stores, and ships proteins from the ER

CIS vs TRANS Golgi face

CIS

• receiving side, where vesicles enter

TRANS

• shipping side, where vesicles exit

lysosome

breaks down larger molecules w/ hydrolytic enzymes

hydrolytic enzymes

enzymes that break down molecules by adding water

phagocytosis

• engulfing (food) solids/partices into a vacuole

• brining vacuole into the cell

• active transport

pinocytosis

• engulfing (extracellural) fluids, brining them into the cell

• active transport

autophagy

recycling of a cells own organic material using lysosomal enzymes

vacuoles

large vesicles from the ER and Golgi

types of vacuoles

• food vacuole - stores food for digestion

• contractile vacuole - structure that pumps excess water out of freshwater unicellular organisms

• central vacuole - large plant cell storage of water and ions

mitochondria

where cellular respiration takes place

ATP is produced

cellular respiration

metabolic process that uses oxygen to generate ATP by taking energy from sugars, fats, ect.

cristae

folds of the mitochondrial inner membrane that increases surface area

endosymbiotic theory

early eukaryotic ancestor engulfed a prokaryotic cell which eventually became a symbiotic organelle

chloroplasts

organelle where photosynthesis occurs

found in plants and algae

chlorophyll

green pigment involved in the photosynthetic production of glucose

why plants are green

thylakoids

sacs inside chloroplasts where light reaction of photosynthesis occurs

granum

stack of flattened thylakoids

stroma

fluid surrounding thylakoids, site of light-independent reactions

peroxisomes

specialized compartments containing enzymes that break down molecules and detoxify hydrogen peroxide

cytoskeleton

network of fibers that organized cell structures and activities

maintains cell shape

motor proteins

proteins that attach to cytoskeleton and move materials within the cell

microtubules

hollow tubes involved in centrioles, cilia, and flagella

microfilaments

intertwined strands of actin involved in movement

intermediate filaments

fibrous proteins supercoiled into strong cables

centersome

organizing center in animal cells

centrioles

structures inside centersomes arranged in 9 microtubel triplets

cilia

structures used for movement found in LARGE numbers

flagella

structures used for movement found singularly or in few numbers

cell wall

rigid plant cell covering made of cellulose

primary cell wall

thin, flexible wall secreted by young plant cells

middle lamella

pectin-rich layer that helps glue plant cells together

secondary cell wall

thicker wall layer created by older plant cells

plasmodesmata

channels between plant cells that allow communication and material transfer

extra cellular matrix

proteins and polysaccharides secreted by cells

surround animal cells

tight junctions

junctions that prevent leakage between adjacent cells

desmosomes

anchoring junctions that hold cells together in strong sheets

gap junctions

animal cell channels that allow materials to pass between cells

plasma membrane

selectively permeable barrier surrounding a cell

phospholipid

membrane lipid with hydrophilic head and hydrophobic fatty-acid tails

amphipathic

having both hydrophilic and hydrophobic regions

phospholipid bilayer

two layers of phospholipids forming the basic structure of the cell membrane

fluid mosaic model

membrane as a flexible bilayer w/ embedded proteins

frye and edidin experiment

Mouse and human membrane proteins mixed over time, demonstrating membrane fluidity

unsaturated fatty acids

helps membranes remain fluid at low temperatures (plants)

cholesterol

helps membranes remain fluid across temp changes (animals)

• rigid at high temp

• fluid at low temp

integral proteins

proteins extending partly or completely though the membrane

transmembrane proteins

integral proteins that span the entire membrane

peripheral proteins

proteins located entirely outside lipid bilayer

glycoproteins / glycolipids

membrane proteins/lipids with attached carbs used in cell recognition

oligosaccharides

short carb chains that act as cell markers

aqua porins

channel proteins that facilitate water movement across the membrane

cytoskeleton attachement

Membrane proteins can attach to the cytoskeleton to help maintain cell structure.

extra cellular matrix attachment

proteins attached ti the ECM for support

functions of membrane proteins (6)

• transport

• enzymatic activity

• signal transmission

• cell recognition

• intercellular joining

• attachement to the ECM or cytoskeleton

selective permeability

The membrane allows some substances through more easily than others.

transport proteins

membrane proteins that help hydrophilic substances cross the membrane

channel proteins

proteins that provide passageways for substances to cross membrane

carrier proteins

proteins that bund specific substances and change shape to move them across the membrane

gated ion channels

channels that open or close based on stimulus

ligand

• the thing that opens gated channels

• A molecule that binds to a protein, potentially triggering a response such as opening a gated channel.

cell recognition

identification of cells using membrane carbs attached to proteins and lipids

diffusion

Net movement of molecules from an area of high concentration to an area of low concentration

kinetic energy

energy of motion that causes molecules to move randomly

concentration gradient

Difference in concentration of the same substance between two areas.

dynamic equalibrium

Molecules continue moving equally in both directions, resulting in no net movement

passive transport

movement of substances down the concentration gradient without using cellular energy

factors affecting diffusion (4)

• temp

• concentration gradient

• movement

• charge

facilitated diffusion

passive movement of polar molecules or ions through transport proteins from high to low concentration