Ch. 2 - Cells

Question 1

Phospholipid membrane permeability – ______ (polar can only if ___) and hydrophobic molecules can ___ across the membrane. Everything else requires ___ (large, polar, charged molecules).

Answer 1

___
small, uncharged, nonpolar molecules
small and uncharged

freely pass

transporter

Question 2

peripheral membrane proteins are generally ___; held in place by H-bonding and electrostatic interaction. Disrupt/detach by changing ___ or ___ to disrupt these interactions.

Integral proteins are ___; use ___ to destroy membrane and expose these proteins

Answer 2

hydrophilic
salt conc.
pH

hydrophobic
detergent

Question 3

• Channel proteins: provide passageway through membrane for ___ (water-soluble) substances (polar, and charged).

**- Recognition proteins: such as major-histocompatibility complex on macrophage to distinguish between self and foreign; they are ___ due to oligosaccharides attached.

Answer 3

hydrophilic

glycoproteins

Question 4

• Ion channels: passage of ions across membrane. Called gated channels in nerve and muscle cells, respond to stimuli. Note that these can be ___ (respond to difference in membrane potential), ___ (chemical binds and opens channel), or ___ (respond to pressure, vibration, temperature, etc).

**- Porins: allow passage of certain ions + small polar molecules. ___ increase rate of H2O passing (___). These tend not to be specific, they’re just large passages, if you can fit you’d go through.

Answer 4

voltage-gated
ligand-gated
mechanically-gated

aquaporins
kidney and plant root cells

Question 5

• Carrier proteins: bind to ___, protein changes shape, molecule passed across. E.g. ___ into cell.(this is a type of transport protein). Carrier seems to be specific to movement across membrane via integral membrane protein.

Answer 5

specific molecules

glucose

Question 6

• Transport proteins: can use ATP to transport materials across (___ ). Active transport. E.g. Na+-K+ pump to maintain gradients. ___ as well. Transport protein is a broad category that encompasses many of the above.

**- Adhesion proteins: attach cells to ___ , provide ___ for internal filaments and tubules (stability)

• Receptor proteins: binding site for ___ + other trigger molecules

Answer 6

not all transport use ATP
facilitated diffusion

neighboring cells
anchors

hormones

Question 7

• Cholesterol: adds ___ to membrane of ___ under normal conditions (but at low temperatures it ___); sterols provide similar function in ___. Prokaryotes do not have cholesterol in their membranes (use ___ instead)

Answer 7

rigidity
an animal cell
maintains its fluidity

plant cells

hopanoids

Question 8

**- Glycocalyx: a ___ coat that covers ___ of some bacteria and ___ (some animal cells). It consists of ___ (attached to plasma membrane) and ___ (such as recognition proteins). It may provide adhesive capabilities, a ___, or markers for cell-cell recognition.

Answer 8

carbohydrate
outer face of cell wall
outer face of plasma membrane

glycolipids
glycoproteins
barrier to infection

Question 9

• Nucleus: ___ is the general packaging structure of DNA around proteins in eukaryotes, the tightness of the packaging varies depending on ___; ___ is tightly condensed chromatin when the cell is ready to divide; histones serve to organize DNA which coil around it into ___

Answer 9

chromatin
cell stage
chromosomes
bundle nucleosomes (8 histones)

Question 10

___ inside the nucleus are the maker of ribosomes (rRNA). rRNA is synth’d in ___ + ribosomal proteins ___ = ribosomal subunits form; these subunits are ___ to the cytoplasm for final assembly into complete ribosome.

Answer 10

nucleolus
nucleolus
in the cytoplasm
exported

Question 11

Nucleus bound by ___ nuclear envelope w/ nuclear pores for transport (mRNA, ribosome subunits, dNTPs, proteins like RNA polymerase + histones, etc) in/out. Note there is no “cytoplasm” in nucleus, there’s a ___ instead.

Answer 11

double layer

nucleoplasm

Question 12

**- Nuclear Lamina: dense fibrillar network inside nucleus of ___ (___ + ___). Provides mechanical support; also helps regulate ___, ___, chromatin organization.

Answer 12

eukaryotic cells
intermediate filaments + membrane associated proteins
DNA replication
cell divison

Question 13

• Nucleoid: irregular shaped region within the cell of ___ that contains all/most generic material

Answer 13

prokaryote

Question 14

• Cytoplasm: this is an ___, not a ___! metabolic activity and transport occur here. ___ is streaming movement within cell. Doesn’t include ___, but does included cytosol, organelles, everything suspended w/in cytosol but nucleus

Answer 14

area
structure
cyclosis
nucleus

Question 15

• Cytosol: difference vs cytoplasm here (cytosol doesn’t include the stuff suspended within the gel-like substance, it is ___. Think jello vs veggie stew.) (the cytosol is also known as ___)

Answer 15

just the gel-like stuff

cytoplasmic matrix

Question 16

• Ribosomes: ___ = 80S, prokaryote (___ = 70S); the two subunits produced inside the nucloleus moved into the cytoplasm where they assembled into a single 80S ribosomes (larger S value indicates ___). Made of rRNA+protein, function to make proteins.

Answer 16

60S + 40S
50S + 30S

heavier molecule

Question 17

**- ER: rough ER (with ribosomes) creates glycoproteins by attaching ___ to polypeptides as they are assembled by ___. In eukaryotes the rough ER is ___ with the outer nuclear membrane.

Smooth ER (no ribosomes) synthesizes ___ for export. In liver cells, smooth ER has functions in breakdown toxins, drugs, and toxic by-products from cellular rxn. Smooth and striated muscle have smooth ER’s called ___ that store and release ions, e.g. Ca 2+

Answer 17

polysaccharides
ribosomes
continuous

lipid and steroid hormoes
sarcoplasmic reticulum

Question 18

**- Lysosomes: vesicles produced from Golgi that contain digestive enzymes (___ for function); break down nutrients/bacteria/cell debris. Any enzyme that escape from lysosomes remains ___ in the neutral pH of cytosol (other source says autolysis) (lysosomes in plant cell – maybe, but generally taught as none). Functions in ___ (releases contents into cell).

Answer 18

low pH
inactive
apoptosis

Question 19

• Golgi: transport of various substances in vesicles (___ face is for incoming vesicles, trans face for secretory vesicles). Has flattened sacs known as ___.

Answer 19

cis

cisternae

Question 20

**- Peroxisomes: break down substances (H2O2 +RH2 => R + 2H2O), fatty acid, and amino acid; common in ___ where they break toxic substances.

In plant cell, peroxisomes modify by-products of ___.

In germinating seeds, it is called ___ break down stored fatty acids to help generate energy for ___. Peroxisome produce ___ which they then use to oxidize substrates, they can also break down H2O2 if necessary (H2O2 => H2O + O2)

Answer 20

kidney and liver

photorespiration

glyoxysomes
growth
H2O2 (hydrogen peroxide)

Question 21

**- Microtubules: made up of protein ___, provide support and motility for cellular activities; ___ which guide chromosomes during division; in flagella and cilia (9+2 array; 9 pairs + 2 singlets in center) in all ___ (mosses, ferns).

Answer 21

tubulin
spindle apparatus
animals and lower plants (NOT PROKARYOTES)

Question 22

**- Intermediate filaments: provide support for maintaining cell shape. E.g. ___ .

Answer 22

keratin

Question 23

• Microfilament: made up of ___ and involved in cell motility. (skeletal muscle, amoeba pseudopod, ___)

Answer 23

actin

cleavage furrow

Question 24

**- Microtubules organizing centers (MTOCs): include ___ (are at the base of each ___ and ___). 9x3 array.

Plant cells lack ___ and its division is by ___ instead of cleavage furrow – note that plants DO have MTOC’s.

Answer 24

centrioles and basal bodies
cilium/flagellum
organize their development
centrioles
cell plate

Question 25

- Transport vacuoles: move materials between ___ or organelles and the ___

Answer 25

organelles | plasma membrane

Question 26

- Food vacuoles: temporary receptacles of nutrients; merge with ___ which break down food.

Answer 26

lysosomes

Question 27

- Central vacuoles: large, occupy most of ___ , exert ___ when fully filled to maintain rigidity. Also store nutrients, carry out functions performed by ___ in animal cells. Have a specialized membrane (___ )

Answer 27

plant cell interior turgor lysosomes tonoplast

Question 28

**- Storage vacuoles: plants store ___, pigments, and toxic substances (nicotine).

Answer 28

starch

Question 29

**- Contractile vacuoles: in ___ that collect and pump excess water out of the cells (___). ___ transport. Found in Protista like amoeba and paramecia, organisms live in ___ environment.

Answer 29

single-celled organisms prevent bursting active hypotonic

Question 30

- Cell walls: found in plants, fungi, protists, and bacteria (___ in plants; ___ in fungi; ___ in bacteria, ___ in archea). Provides support. Sometimes a ___develops beneath the primary one.

Answer 30

``` cellulose chitin peptidoglycans polysaccharides secondary cell wall ```

Question 31

**- Extracellular matrix: found in ___, in area between adjacent cells (beyond plasma membrane and glycocalyx); occupied by fibrous structural proteins, adhesion proteins, and polysaccharides secreted by cells; provide mechanical support and helps bind adjacent cells (___ is most common here, we also see ___; network of collagen and proteoglycans connected to ___ in the cell membrane via fibronectin). Laminin can be seen as well (acts similar to ___)

Answer 31

``` animals collagen integrin+fibronectin integrins fibronectin ```

Question 32

cells adhere to the ECM in two ways: ___ (connection of ECM to ___ in the cell) and ___ (connection of ECM to ___ e.g. keratin).

Answer 32

focal adhesions actin filaments hemidesmosomes intermediate filaments

Question 33

- Plastids: found in ___. Chloroplasts (site of ___), leucoplasts (can specialize to store starch/___/protein as amyloplasts/___/proteinoplasts respectively, or serve general biosynthetic fxns), chromoplasts (store ___)

Answer 33

``` plant cells photosynthesis lipid elaioplasts carotenoids ```

Question 34

Mitochondria: make ATP, also ___ (B-oxidation)! (fatty acids are made in ___). Also have their own ___ and ___ (gives rise to endosymbiotic theory!). Have a ___ layered membrane.

Answer 34

``` fatty acid catabolism cytosol circular DNA ribosomes double ```

Question 35

**Cytoskeleton: ___ (ex. flagella & cilia), microfilaments, ___. In eukaryotic cells, aids in ___, cell crawling, and the movement of cytoplasm and organelles.

Answer 35

microtubules intermediate filaments cell divison

Question 36

Note on plant cells: in a ___ solution (their normal state), vacuole swells -> ___. In isotonic, the plant cell is ___. In hypertonic, the cell is ___ – cytoplasm is pulled away from the cell wall. Fungal cells also remain turgid due to cell wall, but animal cells will ___ (cytolysis).

Answer 36

hypotonic turgid flaccid plasmolyzed burst

Question 37

The ___ is the network of organelles and structures, either directly or indirectly connected, that function in the ___ and other macromolecules into or out of the cell. Includes plasma membrane, endoplasmic reticulum, golgi apparatus, nuclear envelope, lysosomes, vacuoles, vesicles, endosomes but not the ___ or ___.

Answer 37

endomembrane system transport of proteins mitochondria chloroplasts

Question 38

INTRACELLULAR Circulation o Brownian movement (particles move due to ___ spreads small suspended particles throughout ___) o Cyclosis/streaming: circular motion of ___ around cell ___ o Endoplasmic Reticulum: Provides channel through cytoplasm, provides direct continuous passageway from ___ to nuclear membrane

Answer 38

kinetic energy cytoplasm cytoplasm transport molecules plasma membrane

Question 39

EXTRACELLULAR Circulation o Diffusion: If cells in close contact with ___, can suffice for food and ___. Also used for transport of materials between ___ and ___ around cells in more complex animals o Circulatory system: complex animals w/ cell too far from ___ require one. Use vessels.

Answer 39

external environment respiration needs cells interstitial fluid external environment

Question 40

**- Anchoring junctions: ___ (keratin filaments inside attach to adhesion plaques which bind ___ together via connecting adhesion proteins, providing mechanical stability, hold cellular structures together). In ___ cells. Present in tissues with ___ – skin epithelium, cervix/uterus

Answer 40

desmosome adjacent cells animal mechanical stress

Question 41

- Tight junctions: completely ___ each cell, producing a seal that prevents the ___; characteristic of cells lining the ___ where materials are required to pass through cells into blood (They prevent the passage of molecules and ions through the ___ between cells. So materials must actually enter the cells (by diffusion or active transport) in order to pass through the tissue). In ___cells.

Answer 41

``` encircles passage of materials BETWEEN cells digestive tract space animal ```

Question 42

Gap junction: narrow tunnels between animal cells (___); prevent cytoplasms of each cell from ___, but allow passage of ions and small molecules; essentially channel proteins of two adjacent cells that are ___ (smooth muscle single of spreading action potential). In ___ cells. Tissue like heart have these to pass ___.

Answer 42

``` connexins mixing closely aligned animal electrical impulses ```

Question 43

- Plasmodesmata: narrow tunnels between ___ cells (narrow tube of endoplasmic reticulum-___; but exchange material through ___ surrounding the desmotubule)

Answer 43

plant desmotubule cytoplasms

Question 44

**Eukaryotes include all organisms except for bacteria, cyanobacteria, and ___. Prokaryotes have a plasma membrane, DNA molecule, ___, cytoplasm, and cell wall. In prokaryotes: 1. ___. 4. Cell walls (___); archea (___) – many have sticky capsules on wall 2. Single (circular) naked ___ DNA (___). 3. Prokaryote (50S + 30S = ___); 5. Flagella are constructed from ___ NOT microtubules in prokaryotes.

Answer 44

archaebacteria ribosomes no nucleus peptidoglycans polysaccharides DS no chromtin 70S flagellin

Question 45

Hypertonic (___ solute concentration), hypotonic (___ solute concentration), isotonic (___ solute concentration)

Answer 45

higher lower equal

Question 46

Bulk Flow = collective movement of substances in the ___ direction in response to a ______ (e.g. blood)

Answer 46

same | force or pressure

Question 47

Passive Transport – - Simple diffusion, osmosis, dialysis (diffusion of different solutes across a selectively permeable membrane), plasmolysis (movement of water out of a cell that results in its ___), facilitated diffusion, countercurrent exchange (diffusion by bulk flow in ___ – blood and water in fish gills). Note: diffusion is ___, some few particles still move against the gradient because molecule movement is ___, but net diffusion is generally what we talk about.

Answer 47

collapse opposite directions net random

Question 48

Active Transport – movement of transports against their concentration gradients ___ energy. Usually solutes like small ions, amino acids, monosaccharides

Answer 48

requiring

Question 49

* Endocytosis: uses ATP (___) (exocytosis is ___) (Cliff’s FC says bulk flow is active too...?) - Phagocytosis: undissolved material (___) enters cell; white blood cell engulfs. Plasma membrane wraps outward around. - Pinocytosis: dissolved material (___). Plasma membrane ___. ``` - Receptor-mediated: a form of ___; specific molecules (___) bind to receptors; proteins that transport cholesterol in blood (___) and hormones target specific cells by this. ```

Answer 49

active process active process solid liquid invaginates pinocytosis ligand LDL (low density lipoproteins)