107 module 2

Question 1

cell theory

Answer 1

1. all organisms are composed of one or more cells
2. the cell is the basic unit of structure and organisation
3. all cells arise only from pre-exisiting cells

Question 2

cell theory - universal similarities between cells

Answer 2

1. DNA as the heritable material, RNA as a messenger and proteins as workers
2. major cellular organelles - functions and arrangements within the cell
3. ATP as energy source

Question 3

the central dogma

Answer 3

DNA -> RNA -> PROTEIN

Question 4

the endomembrane system

Answer 4

nucleus, ER, golgi apparatus, lysosomes along with plasma membrane (work together to package, label and ship molecules)

Question 5

prokaryote vs eukaryote

Answer 5

both have plasma membrane, cytosol, DNA, RNA, protein and ribosomes. Eukaryote cells have membrane bound organelles and are much larger, prokaryotes cells lack a membrane bound nucleus

Question 6

cytoplasm

Answer 6

everything inside plasma membrane including organelles but not including nucleus, fluid portion is called cytosol

Question 7

what is cytosol

Answer 7

water plus dissolved and suspended substances (ions, ATP, proteins, lipids)

Question 8

plasma membrane

Answer 8

selectively permeable barrier controlling the passage of substances in and out cell. Double layer of phospholipids with embedded proteins, physical barrier separating inside/outside of cell..

Question 9

peripheral membrane proteins

Answer 9

associated with membrane but not actually embedded in it

Question 10

integral proteins

Answer 10

embedded either partially or fully into membrane -> eg. transmembrane proteins are integral membrane as they fully span entire membrane contracting both extracellular and cytoplasmic areas.

Question 11

plasma membrane function

Answer 11

allow cell to cell identification and facilitate intercellular communication

Question 12

Plasma membrane proteins function list

Answer 12

1. transport
2. enzymatic activity
3. signal transduction
4. cell-cell recog
   5) intercellular joining
   f) attachment to the cytoskeleton and extracellular matrix

Question 13

transport - plasma membrane

Answer 13

channels, transporters, may be general or selective, gated or not

Question 14

enzymatic activity - plasma membrane

Answer 14

enzymes on plasma membrane that carry out chem reaction, may or may not be part of a team of enzymes

Question 15

signal transduction - plasma membrane

Answer 15

external signaling molecule causing communication of information to the inside of cell

Question 16

cell-cell recognition plasma membrane

Answer 16

gap junctions and tight junctions, function of plasma membrane

Question 17

attachment to cytoskeleton and ECM - plasma membrane

Answer 17

plasma membrane function, eg, fibronectin mediates contact between cell surface integrins and ECM (collagen) -> can facilitate movement.

Question 18

is the plasma membrane static

Answer 18

the membrane is a mosaic of molecules bobbing in a fluid bilayer of phospholipids, cell specific and dynamic repertoire of membrane bound proteins present as required.

Question 19

nucleus

Answer 19

enclosed by double lipid bilayer called nuclear envelope. continuous with rough ER. entry and exit through nuclear pores.

Question 20

nucelolus

Answer 20

rRNA production. assembly of small and large subunits of ribosomes

Question 20

nucleus functions

Answer 20

house/protect DNA
make RNA and assemble ribosomes
pores regulate movement of substances (eg protein and mRNA) in and out
molecule segregation to allow temporal and spatial control of cell function

Question 21

DNA in nucleus

Answer 21

wrapped 2x around a group of 8 histones, to form nucleosomes, as the cell prepares for cell division chromatin condenses to form chromatin fibers then condenses further into loops -> stacks of chromosomes

Question 22

nucleosomes

Answer 22

DNA wrapped 2x around a group of 8 histones

Question 23

DNA IN NUCLEUS CELL DIVISION PREP

Answer 23

DNA wrapped 2x around 8 histones -> nucleosomes (chromatin) -> chromatin fibers -> loops and stacks -> chromosomes

Question 24

ribosomes

Question 25

RER

Answer 25

continuous with nuclear envelope dotted with attached ribosomes, proteins enter lumen for folding. Major function is production of secreted, membrane and organelle proteins

Question 26

smooth er

Answer 26

extends from rough ER. Functions of SER vary greatly from cell to cell -> very cell/tissue type specific. no ribosomes doesnt make proteins. Major function is a housing unit for proteins and enzymes - synthesises lipids (steroids and phospholipids) - storage of cell-specific proteins not all cells make proteins

Question 26

golgi

Answer 26

made up of 3-20 flattened membranous sacs called cristinae - modify sort package and transport proteins received from rough er using enzymes in each cristinae formation of - secretory vesicles (proteins for exocytosis) - membrane vesicles (PM molecules) - transport vesicles (molecules to lysosome)

Question 27

golgi apparatus: to destination

Answer 27

each sac/cristinae contains enzymes of diff functions - proteins move cis -> trans from sac to sac mature at exit cristernae travel to destination modifications at each sac (formation of glycoproteins, glycolipids and lipoproteins).

Question 28

lysosomes

Answer 28

vesicles formed from golgi membrane membrane proteins pump H+ to maintain acidic pH rest of cell protected by membrane

Question 29

lysosomes main function

Answer 29

digestion of substances that enter a cell cell components eg. organelles in autophagy entire cells = autolysis once digested all building blocks (aa, lipids) are recycled.

Question 30

mitochondriballz

Answer 30

outer memb, inner memb with cristae, fluid filled interior = mito matrix more energy needed = more atp = greater no. of mitochondria mitochondria carry a separate small (37 genes) genome encoding mitochondrial specific products.

Question 31

cytoskeleton

Answer 31

fibres or filaments that help maintain size, shape and integrity of cell - act as scaffolding across the cell - involved in intracellular transportation and cell movement three types of fibers microfilaments -> intermediate filaments -> microtubules

Question 32

cytoskeleton microfilaments

Answer 32

diameter ~7nm, comprised of actin molecules assembled in two long chains twisted around each other. found around periphery and lining interior of cell

Question 33

cytoskeleton filaments function

Answer 33

bear tension and weight by anchoring cytoskeleton to plasma membrane proteins and promote amoeboid motility if required (macrophage)

Question 34

What does it mean by cytoskeleton microfilaments being dynamic

Answer 34

assembled and disassembled as required -> dynamic

Question 35

cytoskeleton intermediate filaments

Answer 35

8-12nm diameter comprised of diverse range of different materials eg. keratin. FOund in cytoplasm of cell.

Question 36

function of intermediate filaments of cytoskeleton

Answer 36

bear tension and weight throughout cell. Eg. during cell anchoring act as scaffold of cellular organelles such as the nucleus

Question 37

are the intermediate filaments of the cytoskeleton dynamic?

Answer 37

usually most permanent of cytoskeletal structures, less dynamic.

Question 38

cytoskeleton microtubules

Answer 38

diameter: tubular structure 25nm with central lumen of 15 nm diameter. comprised of tubulin dimers (alpha and beta) coiled to form a tube. extends from centriole into cytoplasm/nucleus

Question 39

cytoskeleton microtubules function

Answer 39

support cell shape and size, guide for movement of organelles (eg vesicles from golgi to membrane) chromosome organisation - cell division support and movement of cilia/flagella

Question 40

are microtubules in the cytoskeleton dynamic

Answer 40

assembled and disassembled as required- are dynamic

Question 42

paracrine comms intercellular comms,

Answer 42

through extracellular fluid, paracrine factors, primary limited to local area where paracrine factor concentrations are relatively high, target cells must have appropriate receptors

Question 43

endocrine communication intercellular comms,

Answer 43

through blood stream via hormones, target cells are primarily in other tissues and organs and must have appropriate receptors

Question 44

intercellular comms: synaptic comms

Answer 44

across synaptic clefts, neurotransmitters, limited to very specific area, target cells must have appropriate receptors.

Question 57

smallest to largest fibers in cytoskeleton

Answer 57

microfilaments -> intermediate filaments -> microtubules