quarter quiz 3 bio 107

All membranes contain

Phospholipids, proteins, carbohydrates

Amphipathic

Both hydrophilic and hydrophobic

Temperature and phophplipid membrane

Temp increases=increase fluidity(more permeable)

Temp decreases=decrease fluidity(more viscous)

Unsaturated fatty acids

More fluid, bends from double bonds increase freedom of movement

Sterols

Regulates fluidity (cholesterol in animal membranes)

Integral proteins

Pass through lipid bilayer, amphipathic

Peripheral proteins

Attached to the surface of the membrane, bind to phopholipid or integral proteins, H bonds or Ionic

Glycoprotein

Carbohydrate attached to integral membrane protein,carbohydarte, used for cell to cell recognition(identify other cells)

Glycolipid

Carbohydrate attached to phospholipid, carbohydarte, used for cell to cell recognition(identify other cells)

Diffusion

Tendency of molecules to move down a concentration gradient

Concentration gradient

Move from high to low Concentration, releases energy

Simple diffusion

Small, or non polar molecules pass through bilayer

Facilitated diffusion

Aided by membrane proteins, no energy required, m9 event occurs with conc gradient

Channel proteins

Form hydrophilic channels that allow specific molecules to pass, aquaporins(water molecules) and ions

Carrier proteins

Change shape when specific molecules bind to carry them across memb, glucose

Osmosis

Diffusion of water across a selectively permeable membrane, water can, solutes cant

Hypertonic

Contains higher solutions concentration

Hypotonic

Contains lower solute concentration

Isotonic

Equal solution concentrations

Concentration gradient for water

Always hypotonic to hypertonic

Cell in hypotonic

Bursts, swells, water moves in, except in organisms with a cell wall(turgid)

Cells in hypertonic

Water moves out, shrivels, except in organisms with cell wall(plasmolysis)

Active transport

Against concentration gradient, moving from low to high concentration, impermiability of membrane allows gradient to for, requires membrane proteins, and energy

Membrane potential

A separation of charges, creates voltage, due to concentration gradient of ions, negative on inside, positive on outside

Primary active transport

Requires transport protien, energy by ATP hydrolysis(causes a change in shape), creates membrane potentials(electrochemical gradient) , proton(H) pump, sodium-potassium pump

Secondary active transport

Uses an ion gradient for energy, transport of solutes is coupled to diffusion of ions, ion gradient created by primary transport that uses ATP as energy source.

Symport

Type of secondary active transport, the transport solution moves in the same direction of the gradient of the driving ion

Antiport

Type of second a ry active transport, the transported solution moves in the opposite direction from the gradient of the driving ion

Membrane vehicle

Small compartments in the cytoplasm

Exocytosis

Cell secretes proteins and other molecules by the fusion of the vehicle with the plasma membrane

Endocytosis

Cells take in materials by forming new vesicles from the plasma membrane, has three different types

1. Phagocytosis, cell engulfs particles using pseuodopidia

2. Pinocytosys, cells engulf non specific extracelluoar fluid

3. Receptor mediated endocytosis, used for uptake of high concentration of specific molecule

Prokaryote

No nucleus, no rganelles, no internal memebrane

Eukaryote

Nucleus, organelles(membrane bound)

Bacterial cell structure

Contains cytoplasm which contains cytoplasm, contains ribosome, nucleoid contains DNA, one chromosome per cell

Bacterial chromosome

circular DNA molecule, protien condensed into histones, contains essential genes

Bacterial plasmid

Small circular peices of DNA found in the cytoplasm, not essential, provides cell with an advantage like antibiotic resistance

Eukaryotic cytoplasm

All cellular contents, between nucleus and cell membrane

Eukaryotic cytosol

The semi fluid portion of the cytoplasm, contains dissolved ions and molecules

Eukaryotic nucleous

Contains genetic material, site of DNA replication and transcription, directs all cell activity

Eukaryotic nuclear envelope

Doubles membrane enclosing the nucleous, covered in pores

Eukaryotic nuclear pores

Control movement of the molecules in And out of nucleous, protein complexes that pass through nuclear envelope

Eukaryotic nuclear lamina

Network of protein filaments, lines inside of nuclear envelope, supports shape of nucleous

Eukaryotic chromosomes

Contain Genetic info, DNA condensed by wrapping around histone proteins

Eukaryotic ribosomes

Synthesize proteins from amino acid monomers(ribosomal RNA, robsomal proteins)

1. Free ribosome, loose in cytoplasm

2. Bound ribosome, attached to outside of ER and nuclear envelope

Eukaryotic endoplasmic reticulum

Network of membrane tubules and sacs called cisternae, inside space called lumen, ER is continouse with nuclear envelope

1. Rough ER, civered in bound ribosomes, site of protien synthesis and protein modification

2. Smooth ER, no bound ribosome, no protiensynthesis, containsenzymes for lipid synthesis, and carbohydrate synthesis

Eukaryotic Golgi complex

Receives material in the ER, modifies proteins and lipids, targets proteins to final destination, flattened sac of cisternae in stacks, two faces cis(recieves vesucles from ER) and trans(vesicles bud off and sent to other sites)

Eukaryotic lysosomes

Membrane bound sac containing hydrolytic enzymes(enzyems function best at acidic pH), catalysts hydrolysis reactions, phagocytosis,autophagy

Eukaryotic Vacoule

1. Food vacoule

2. Contractile vacoule(fresh water protistst to pump out water)

3. Central vacoules(plants, storage)

The endomembrane system

Eukaryotic mitochondria

Not participate of the endomembrane system, site of cellular respiration(makes ATP), double membrane

Eukaryotic chloroplasts

Not part of the endomembrane system, site of photosynthesis, three membranes(inner outer thylakoid), stomach contaisn enzymes ribosomes and DNA

Origins of endomembrane system

Infolding of cell membrane formed nuclear envelopes, ER, and other organlles

Endosymbiotic hypothesis

1. Small porkayotes(bacterium) was engulfed and began living within larger cell(archean)

2. Mutually beneficial relationship developed, and two cells began evolving together

3. Two organisms became dependent on eachother

Serial endosymbiosis

All eukaryotes have mitochondria but only plants have chloroplasts, endosymbiosis happened twice

Two stages

1. Aerobic respir8ng bacterium engulfed =mitochondria

2. Photosynthesis bacterium engulfed only by plant cells=chlorplasts

Evidence of this theory(replicate by binary fission,double membrane, own DNA and ribsosomes)

Eukaryotic cytoskeleton: microtubules

Hollow tubes, large(25 nm), made of turbulence protein, dynamic

• Support cell shape

• Anchor organlles

• Provide pathways for oragnelle and vesicles movement

• Separate chromosomes during mitosis

• Form cilia and flagella in eukaryotes

Eukaryotic cytoskeleton: microfilaments

Two strands twisted around each other, small(7 nm), made of the protein actin, dynamic

• Maintains cell shape-cortex, inside plasma membrane

• Cell division-cytokinsis, last stage of cell division(cleavage furrow)

• Reshaped the cell for phagocytosis and cell crawling

• Cytoplasmic streaming

• Anchors organlles and nucleous

• Supports cell shape

• Forms nuclear lamina

• Forms desmosomes

Eukaryotic cytoskeleton: intermediate filaments

Thick coiled protein fibers, medium(8-12 nm), made of different protein depending on type(ex, keratin), not dynamic

Motor proteins

Drive movement of objects along cytoskeleton filaments, both micrtubules and microfilaments a t as tracks for the movement, hydrolyze ATP causes motor proteins to change shape = walk along filament

Eukaryotic Centrosome

Microtubule organizing center of the animal cell, made of two centrioles at right angles, centriol = 9 MT triplets in a ring

Eukaryotic cilia and flagella

Movement structure made of microtubules, 9+2 structure(9 doublets(connected by dynein) in a ring, 2 single MTs in center), filaments is anchored by cytoskeleton by the basal body(9 triplets of MTs in a ring) all inside the plasma memebrane

Cilia: shorter many per cells, moves like oars

Flagella:longer, one or few per cells, undulating like a snake

Cell walls

Found in bacteria and archea and many eukaryotes(just not animal), made of peptidoglycan

• Protection against mechanical, chemical, and osmotic damage,

• gives cell characteristic shape

• Provide mechanical support for organism

• Barrier ro the entry of large molecules

• Protects from pathogens

• Cell cell intercation

Peptidoglycan

Polysaccaride chains, NAG, NAM, makes up cell wall

Gram positive

Type of bacterial cell wall

Gram negative

Type of bacterial cell wall

Plasmodesmata

Channels through the plasma membrane and cell wall of adjacent plant cells, physically connect cytoplasm, allow passages ions water etc.

extracellular matrix

Found in animals, network of carbohydrates and proteins outside the cell membrane

• Physical support

• Adhesion

• Communication

Made of collagen(protein), proteoglycan(sugar polymer), fibrinectin(protein), integrins(membrane proteins)

• Bacterial capsule

Found in some bacteria, st8cky layer of polysaccaride outside cell wall,

• Protects against dehydration

• Virulence

• Adhesion

Important in forming biofilm

Bacterial flagella

Used for cell movement, external to the cell in prokaryotes, different arrangements, madeof protien flagellin, powered by proton gradient.