BIOL EX 2A- Cell and Membrane Parts

Zanzor - Expanding on the cell

prokaryotic

cells that make bacteria and archae

the cell

fundamental unit of life

cell theory

all cells are derived from pre-existing cells

all life is made of cells

simpler to use many small cells than 1 large cell

SA:V ratio allows regulation of tinier molecules

why cells are necessarily small units of large organisms

efficient exchange of materials

a small cell with high SA:V ratio allows for…

magnification

resolution

contrast

(3) basic principles of microscopy

magnification

ratio of an object’s image size compared to its real size

resolution

measure of clarity of the image or

minimum distance of 2 distinguishable points

contrast

visible differences in parts of the sample

light microscopy

views living cells at a low resolution

uses cytotoxic stains to isolate items

fluorescence

stains bind to different molecules for visibility under UV light

SEM

a 3D view of the surfaces of cell structures

TEM

a 2D view through a specimen

cell fractionation

breaks open cells and separates internal components by size and shape

only works on dead cells

centrifugation

exaggerates gravitational force to separate cells into organelles by wt

going faster & taking longer

in centrifugation, each round pellets out smaller parts by…

plasma membrane

cytoplasm

DNA

ribosomes

(4) universal features of ALL cells

nucleoid

unbound region that holds DNA in a prokaryote

membrane-bound organelles

nucleus

larger, more complex

endomembrane system/cytoskeleton

in eukaryotes only

prokaryote is a descriptive term, not a taxon

remember about prokaryotes

fimbriae

strands of protein on bacteria that allow it to attach to other surfaces (not cilia)

nucleoid

dense mass of DNA, occupies large space moving freely around cytoplasm

ribosomes

fx: protein synthesis in cytosol (free) and ER(bound)

size of bacterial and archael ribosomes is a bit different from eukaryotic ribosomes

this is very important in the treatment of bacterial diseases

plasma membrane

manages movement of material into and out of the cell

ONE phospholipid bilayer

cell wall

made of peptidoglycan (bacteria) or pseudopeptidoglycan (archaea)

capsule

structure that helps pathogens stick together to host (made of gooey polysaccharide)

flagella

used for locomotion (to propel prokaryotes toward a stimulus)

bacterial chromosome

loop of DNA that encodes all necessary info for the cell to divide and reproduce

mitochondria

nucleus

ribosomes

ER

golgi ap.

cytoskeleton

plasma membrane

peroxisomes

in BOTH animal and plant cell organelles

peroxisomes

produce hydrogen peroxide

nucleus

used for storage of DNA

is usually most visible organelle

chromosomes

compacted DNA & proteins

chromatin

UNcompacted DNA & proteins

nuclear lamina

woven protein lining that supports nuclear envelope to prevent collapsing in on DNA

nuclear envelope

Double phospholipid bilayer that encloses the nucleus

separation of cytoplasm and nucleus

nuclear pore

regulates entry & exit of the nucleus (within envelope)

nucleolus

makes ribosomal RNA & ribosome subunits

nucleus

chromosomes

lamina

envelope

pore

nucleolus

(6) parts of the nucleus

plasma membrane

used to protect the cell by sorting entry into the cell

smooth ER

lacks ribosomes

synthesizes lipids

metabolizes carbs

detoxifies drugs and poisons

stores Ca² ions

rough ER

bound ribosomes secrete glycoproteins

distributes transport vesicles

membrane factory for the cell

glycoproteins

proteins bonded to carbs

vesicles

transport proteins surrounded by membranes

golgi apparatus

shipping & receiving center

packaging & export of biochemical products

made of cisternae (flat membrane sacs)

vacuoles

food: cellular eating

contractile: removal of excess water

central: holds org. compounds & H2O

lysosomes

hydrolysis of large biomolecules at low pH

they replicate independently

they have their own DNA & ribosomes

double membranes

evidence for endosymbiont theory

rickettsiales & cyanobacteria

extant bacteria linked to mito. & chloro.

mitochondria

site of cellular respiration

chloroplasts

performs photosynthesis, capturing solar energy to make sugars

thylakoids: flattened sacs

grana: stacks of thylakoids

stroma: fluid around grana

structures (3) in chloroplasts

cristae: folded inner membrane, increase SA

matrix: inner fluid

intermembrane space

structures (3) in mitochondria

cytoskeleton

network of fibers extending throughout the cytoplasm

organizes the cell’s structures & activities

anchors organelles

microfilaments, intermediate filaments, microtubules

cytoskeleton elements in increasing order

microfilaments (actin)

fx: pseudopodia, cytoplasmic streaming, muscle contraction (myosin)

intermediate filaments

fx: provide shape to nuclear lamina

anchor organelles, made of keratin

form part of the extracellular matrix

microtubules

fx: form cilia, flagella & cellular monorails

cell division

maintain cell shape to resist compression

tight junction

desmosomes

gap junctions (animals ^)

plasmodesmata (plants)

(4) extracellular components and cellular junction

tight junction

large sections of intercellular joining to prevent leakage

desmosomes

anchor junctions, analogous to rivets

gap junctions

communication junctions

plasmodesmata

allows passage of materials through cell wall (for plants)

selective permeability

a membrane allows some molecules to pass freely while blocking others

50% protein

40% lipids

10% carbs

the chemical composition of cellular membranes

hydrophilic head facing out

hydrophobic tail facing in

phospholipids have…

fluid mosaic model

cell membrane is a phospholipid bilayer w/ proteins embedded throughout, forming a flexible. constantly moving structure

transport

cell-cell recognition

signal transduction

enzymatic activity

intercellular joining

attachment to cytoskeleton (ECM)

(6) major functions of membrane proteins

transport

moves molecules across the membrane

cell-cell recognition

glycoprotein indicate the cell is in proper position relative to its neighbors

signal transduction

receptors bind signals

enzymatic activity

speeds up reactions

intercellular joining

cell-cell anchorage, tight junctions and desmosomes

attachment to cytoskeleton (ECM)

helps maintain cell shape/stability

hydrophobic can

polar can’t

in the selective permeable bilayer:

hydrophobic molecules ___ pass

polar molecules ___ NOT pass, easily

facilitated diffusion

passive movement of molecules across a cell membrane from an area of LOW concentration to an area of HIGH concentration

used in polar molecules & ions

passive transport

• moves gases across the plasma membrane

• diffusion of a substance across a membrane w/ no energy investment

diffusion

dispersion of molecules from an area of HIGH concentration to LOW con.

osmosis

diffusion of water from LOW to HIGH con.

dynamic equilibrium

molecules move in both directions, but have no net charge in concentration

hypotonic

gain water and swell/burst

lower solute concentration outside of the cell than inside

so: cells ___ & ___

hypertonic

lose water and shrink

higher solute concentration outside the cell than inside

so: cells ___ & ___

isotonic

equal solute conc. in and outside the cell

no net water movement across membrane

osmoregulation

control of water & solute conc. balance within an organism

needed for homeostasis in cells

active transport

uses energy to move solutes against gradient flow

understand the sodium-potassium pump

understand the sodium-potassium pump

bulk transport

• active transport using vesicles to move large molecules in/out of plasma membrane

• with or w/o concentration gradient

exocytosis

moving large molecules out of the cell

endocytosis

phagocytosis, pinocytosis, receptor-mediated

moving large molecules into the cell

3 types

1. receptor-mediated

2. phagocytosis

3. pinocytosis

1. binding ligand which trigger vesicle formation

2. cellular eating

3. cellular drinking

1. ER

2. Gogli Apparatus

3. Nuclear Envelope

4. Lysosomes

5. Peroxisomes

6. Vacuoles

(6) components of endomembrane systems