Cell Biology

AP Biology

active transport

• ATP is hydrolyzed

• E and ATP required

• two types are bulk transport and protein pumps

protein pumps

• type of active transport

• used to move small molecules against the concentration gradient (low —> high)

• changes the shape of the protein to facilitate transport across the membrane.

bulk transport

• type of active transport

• mvt of large molecules

  • requires cell mambrane to change in shape

• ie) exocytosis, endocytosis

exocytosis

• active transport

• cell membrane changes shape

• secretion of large molecules out of the cell

• vesicles carrying cellular products fuse w/ the cell membrane and release contents out to the ec fluid

endocytosis

• active transport

• cell membrane changes shape

• secretion of large molecules into the cell

• cells take in targe molecules by forming new vesicles from the cell membrane

What are the three types of endocytosis?

phagocytosis, pinocytosis, receptor-mediated endocytosis

Phagocytosis

• type of endocytosis

• intake of cells or really large molecules

pinocytosis

• type of endocytosis

• intake of medium-sized molecules

receptor-mediated endocytosis

• type of endocytosis

• requires that a receptor be activated in order to engage the process of intake

aquaporins

• channel proteins that facilitate the transport of water across cell membranes.

bproteins

• true polymers

• contain CHON(S)

what is the monomer for proteins?

amino acids

what are amino acids made up of?

• C2 skeleton

• amino group: NH2

• carboxyl group: COOH

• variable side chain attatchment- R-group

  • only distinction between amino acids

what are amino acids linked together form?

polypeptides

biological membranes

• seperate inside water from outside water (cytoplasm from ec fluid)

• selectively permeable

• fluid mosiac model

  • composed of the phospholipid bilayer and embedded/attatched proteins

endosymbiotic theory

• the first eukaryotic membrance-bound organelles were once prokaryores

  • the mitochondria and the chloroplast were once prokar cells that were engulfted by larger prokar cells

what is the importance of compartmentalization?

allows for diff metabolic processes to occur simultaneously —> greater cell efficiency

what is the importance of the sa:vol ratio?

• as a cell grows in size, the vol increases at a much faster rate than the SA

• for exchange of materials to be effective, sa:vol ratio has to be large

what impact does the SA:vol ratio have?

• smaller cells have a higher sa:vol ratio —> increased rate of exchange —> more efficient —→ cell viability

• smaller cells = higher sa:vol ratio

• smaller cells = better

• high sa:vol ration = better

what are phospholipids composed of?

• phosphate head

  • polar hydrophilic (water liking)

• two fatty acid tails

  • nonpolar and hydrophobic (water fearing)

why is the membrane referred to as the fluid mosaic model?

• fluid

  • phospholipids and proteins can move/are flexible BUT must stay in the same embedded laters

• mosaic

  • diff specialized cells have their own unique collection of attached/embedded proteins ion their membranes

what are the two different kinds of membrane proteins?

integral and peripheral proteins

integral proteins

• embedded in the phospho bilayer

• have both polar and nonpolar regions

• transmembrane

  • spans both phosopholipid layers

peripheral proteins

• attatched to the surface of the membrane

• not embedded in the bilayer

glycoproteins

• integral proteins w/ carb antigen attachments that serve as identification tags

• type of cell recognition protein

glycolipids

• membrane lipids w/ carb antigen attatchments

• type of cell recognition protein

cell wall

• outside the cell membrane

• provides structural boundary and added protection

• reduces transport across the membrane

• found in prokaryoes, plants, adn fungi

• composed of polysaccharides

  • plants cell walls are composed of cellulose

  • fungus cell walls are composed of chitin

passive transport

• atp not hydrolyzed

  • no e required

• spontaneous

  • allowed for by entropy

• mvt of small molecules/ions down the concentration gradient

• three types

  • diffusion

  • osmosis

  • facilitated diffusion

diffusion

• type of passive transport

• mvt of small nonpolar molecules down the concentration gradient until equilibrium is reached

osmosis

• type of passive transport

• slow diffusion of h2o down the concentration gradient until equilibrium is reached

facilitated diffusion

• type of passive transport

• small polar molecules/ions down the concentration gradient with the assistance of a channel or carrier protein

• channels and carriers must be signaled to open

sodium-potassium pump

• 3 sodium ions are pumped out of the cell for eery 2 postassium ions pumped into the cell

• serves to maintain the electrochemical gradient across cell membranes

what organelles does the endomembrane system involve?

• nucleus

• rough ER

• smooth ER

• golgi apparatus

• vesicles

• cell membrane

what is the purpose of the endomembrane system?

• modify, package, and transport lipids and proteins out of the cell

hypotonic environment

• has a lower solute concentration in comparison to the cell cytoplasm

• water flows into the cell

  • salt sucks!

• cell swells in size

hypertonic environment

• higher solute concentration in comparasin to the cell cytoplasm

• water flows out of the cell'

  • salt sucks!

• cell shrinks in size

isotonic environment

• equal solute concentration to the ceel cytoplasm

• no net flow of water

  • there still IS mvt, just at the same rate

• no change in cell size

osmoregulation

multicellular organisms will osmoregulate to maintain their preferred env

• regulate the flow of water across their cell membranes to maintain homeostasis

what environment do animal cells prefer?

isotonic environments

• hypotonic solutions would make the cells lyse (explode)

  • water would move into the cell

• hypertonic solutions would make the cells crenate (shrivel up)

what env to plant cells prefer?

hypotonic env

• allowed for my cell wall

• allows plants to stand upright

• hypotonic cells and cell walls allow for turgid (very firm) cells

  • isotonic env would make cells flaccid (limp)

  • hypertonic cells would make the cells plasmolyze (membrane detaches from cell wall)

plasmolysis

the detatchment of the cell membrane from the cell wall is hypertonic cultutions

• water moves out of the cell and thus shrinks in size, causing the membrane to be “less full” and detatch from cell wall

know how to calculate water potential

please!

cell theory

1. cells are the basic unit of life

2. all living things are made up of cells

3. all cells come from other cells

concentration gradient

the process of solutes moving through a solution from an area with a higher number of particles to an area with a lower number of particles

extracellular fluid

the “outside water”

fluid on the outside of the cell

prokaryotic cell

• cell with no membrane bound organelles

carbohydrates

• monomers: monosaccharides

• composed of CHO in a 1:2:1 ratio

• -ose ending

• 3 main fucntion

  • imediate source of E

  • glucose storage

  • cell structure

• covalent bond is called glycocidic linkage

lipids

• composed of CHO(P)

• “sort of” monomers: fatty acids and glycerol

• hydrophobic + extremely nopolar

• covalent bond is called ester linkage

• three major families

  • triglyceride

  • phospholipid

  • steroid

how can you tell the difference between saturated and unsaturated fats?

• saturated fats contain only single bonds between carbon atoms

• unsaturated fats contain double bonds between carbon atoms and a kink at every double bond

triglyceride

• composed of three fatty acid tails and a glycerol

• held tg by ester linkages

• fats

  • triglycerides in animals

  • solid @ room temp

  • contains only saturated fatty acids

• oils

  • triglycerides in plants

  • liquid@ room tempcontains unsaturated fats

phospholipid

• major component of biological membranes

• gyceroolecule and two fatty acid tains

• hydrophilic (water-liking) and polar glycerol+phosphate head

• hydrophobic (water-fearing) and nonpolar fatty acid tails

 

steroids

• characterized by four ring structure

• all derivatives of cholesterol

• extremely nonpolar

Nucleic Acids

• composed of CHONP

• monomer is nucleotides

• 3 components

  • 5 carbon sugar

  • phosphate group at 5’

  • nitrogenous base @ 1’ (only thing that changes between nucleotides)

• held tg by phosphodiester

• types of nucleic acids

  • DNA

  • RNA

  • ATP

DNA

• deoxyribonucleic acid

• codes for proteins

• contains only AGCT

• double stranded helix

• anti-paralllel strands

  • held tg by h-bonds

RNA

• ribonucleic acids

• single strand

• contain AGCU

ATP

• adenosine triphosphate

• structure

  • 5 carbon sugar ribose

  • nitrogen base adenine

  • 3-phosphate groups

• made my cellular respiration or fementation

• e molecule of life

proteins

• monomer: amino acids

• 20 diff amin acids

• structure

  • C2 membrane/skeleton

  • amino group (NH2)

  • carboxyl group (COOH)

  • variable side chain attachment/r-group

    • only thing that changes between amino acids

• covalent bond: peptide bond

Different Levels of Protein Structure

1. Primary

• amino acid sequence held by peptide bonds

2. secondary

• a-helix or b sheet

• caused by h-bonds btwen amino and carboxyl group

3. tertiary structure

chaperones

• assist the folding of other proteins into their functional third degree globular shape

• can be used after denaturation OR when a protein is newly synthesized

• not available for all proteins

flagella

• used for mvt in warer

• attached to the membrane of some animal cells

• attached to the cell wall of some prokaryotes

• tail-liike extension

endoplasmic reticulum

• rough er is involved w the synthesis of proteins

• smooth er produces lipids, breakdown alcohol and drugs

• found in the cytoplasm following the nucleus

• membrane bound

• ribosomes attatched to the rough but not the smooth

central vacuole

• used for storage of water

• gives plants cells structure and rigidity

• free flowing in the cytoplasm occupies the max amt of space available within the cell

• large membrane-bound sac

cytoskeleton

• provides and supports cell shape

• extends throughout the cytoplasm

• not membrane bound

• network of protein fibers extending throughout the cytoplasm

microtubules

• largest cytoskeleton fiber

• can be created and disassembled

• what composes spindle fibers

• compose flagella and cilia

• provide tracks for motor proteins

intermediate filaments

• intermediate cytoskeleton fiber

• permanent structures

• involved in maintaining cell shape and anchoring organelles

microfilaments

• narrowest cytoskeleton fiber

• can be created and disassembled

• involved in muscle cell contraction

mitochondria

• site of cellular respiration

• synthesizes ATP

• free floats throughout cytoplasm

pili

• used to attatch surfaces and other bacterial cells

• used for conjugation

  • transfer of plasmids btwen two diff bacterial cells

centrioles

• cytoskeleton proteins reesponsible for pulling replicated chromosomes apart during cellular division

• found near the nucleus

golgi apparatus

• processing and packaging center of the cell

• modifies and packages proteins

• proteins packaged into vesicles for distribution outside of cell

ribosome

• makes proteins

• free floating in the cytoplasm

• found attached to the rough er in eukar

nucleus

• houses of chromatin

• control center of the cell

• typically at the center of the cell

nucleolus

• makes ribosomes

• free floating inside the nucleus

cell wall

• gives plants structure and rigidity and protection

• lays outside the cell membrane

chloroplast

• site of photosynthesis

  • solar e converted into chemical e

• free-floating in cytoplasm

plasmid

• carry extra bacterial genes

  • genes that are typically not required for survival

• free floating in the cytoplasm

lysosomes

• sacs that contain digestive enzymes that break down old organelles, waste, nutrients, and invading bacterial cells

• free floating in the cytoplasm

cytoplasm

• semi-fluid container for all the cell’s content

• aids in cell shapeprovides chemical respurces for biochemical rxns

• occupies entire available volume of cell

vesicles

• temporary sacs used for transport eithin the cell

• free floating in the cytoplasm

nucleoid

• region where bacterial chromosome is located

• cytoplasm of prokaryotics cells

chromatin

• used to compact the DNA that serves as genetic material

• inside the nucleus

gap junction

• increased communication btwn neighboring cells in a tissue

• embedded as protein channel within the cell membranes of two adjacent cells

plasmodesmata

• increase communication and flow of water and materials btwn neighboring plant cells

• found in breaks in the cell walls of adjacent plant cells