Cells, Membranes, and Signaling (U4)

Question 1

What are the three points of the cell theory?

Answer 1

1. all organisms are made of cells
2. the cell is the basic living unit of organization
3. all cells come from pre-existing cells

Question 2

What are structures all cells have?

Answer 2

plasma membrane, cytosol, chromosomes, and ribosomes

Question 3

Why can’t a cell be bigger?

Answer 3

volume increases faster than surface area and cells cannot move materials in and out fast enough to support life

Question 4

How does a cell get bigger?

Answer 4

it divides and becomes multicellular

Question 5

Ratio

Answer 5

surface area/volume

Question 6

Prokaryotes

Answer 6

generally smaller/simpler, no nucleus or organelles

Question 7

Eukaryotes

Answer 7

generally bigger/more complex, nucleus and organelles

Question 8

Compartmentalization

Answer 8

when internal membranes in eukaryotic cells partition the cell into compartments which creates different local environments

Question 9

Nuclear envelope

Answer 9

protects DNA, allows for large macromolecules to pass through pores which controls protein synthesis

Question 10

Nucleolus

Answer 10

within the nucleus, builds ribosomes from rRNA and proteins which exit through the nuclear pores

Question 11

Ribosomes

Answer 11

create proteins, made of rRNA and protein (2 subunits)

Question 12

Free ribosomes

Answer 12

suspended in cytosol, synthesize proteins in cytosol

Question 13

Bound ribosomes

Answer 13

attached to the ER, synthesize proteins for export or the membrane

Question 14

Endomembrane system

Answer 14

the endoplasmic reticulum, golgi apparatus, lysosomes, and vesicles

Question 15

Autogenic hypothesis

Answer 15

the origin of the eukaryotic cell is also the prokaryotic cell

Question 16

Smooth endoplasmic reticulum

Answer 16

synthesizes lipids, hydrolysis, membrane production, and detoxify drugs and poisons

Question 17

Rough endoplasmic reticulum

Answer 17

contains ribosomes, produces proteins for export out of the cell

Question 18

Golgi apparatus

Answer 18

sorts, tags and ships cell products through vesicles

Question 19

Vesicles

Answer 19

transport cell products through the fusing with cell membranes

Question 20

Lysosomes

Answer 20

found in animal cells, made by rough ER, used to clean up macromolecules and broken down organelles

Question 21

Mitochondria energy conversion

Answer 21

cellular (aerobic) respiration, breaks down sugars, fats, and fuels in the presence of oxygen

Question 22

Chloroplast energy conversion

Answer 22

transforms solar energy into chemical energy

Question 23

Mitochondria

Answer 23

highly folded (cristae) and two membranes, which increases surface area

Question 24

What are the three parts of the chloroplast?

Answer 24

Stroma, thylakoids, and grana

Question 25

Endosymbiotic theory

Answer 25

chloroplasts and mitochondria both have circular chromosomes, are semi-autonomous, and contain proteins primarily from free ribosomes in the cytosol

Question 26

Vacuoles

Answer 26

transferring cell products, storage, turgor pressure in plants

Question 27

Cytoskeleton

Answer 27

maintains shape of the cell and provides anchorage, regulates and allows for motility
made of microfilaments and microtubules

Question 28

Phospholipids

Answer 28

hydrophilic head and hydrophobic tail, arranged in a bilayer

Question 29

Fluid mosaic model

Answer 29

the arrangement of the phospholipid bilayer and proteins together makes a mosaic that can move in “waves” almost like a liquid

Question 30

Peripheral proteins

Answer 30

proteins loosely bound to the outside of the cell wall (ex. antigens)

Question 31

Integral/transmembrane proteins

Answer 31

proteins that penetrate the lipid bilayer, usually across the whole membrane (ex. sodium-potassium pump)

Question 32

Membrane carbohydrates

Answer 32

allows cells to distinguish one another, key in development of organs and immune response

Question 33

Selectively permeable membrane

Answer 33

the cells ability to let some molecules through and others not

Question 34

2nd law of thermodynamics

Answer 34

the universe tends towards entropy (disorder)

Question 35

Simple diffusion (passive transport)

Answer 35

movement from high to low concentration (no energy required)

Question 36

Facilitated diffusion

Answer 36

diffusion through protein channels (no energy needed)

Question 37

Osmosis

Answer 37

the diffusion of water

Question 38

Aquaporins

Answer 38

water channels

Question 39

Hypotonic

Answer 39

(a cell in fresh water) a high concentration of water around the cell

Question 40

Hypertonic

Answer 40

(a cell in salt water) a low concentration of water around the cell

Question 41

Isotonic

Answer 41

a cell in a mild salt solution, no net movement

Question 42

Passive transport

Answer 42

diffusion of molecules with the concentration gradient

Question 43

Active transport

Answer 43

diffusion against the concentration gradient

Question 44

Sodium-potassium pump

Answer 44

enzyme for maintaining osmotic equilibrium

Question 45

How are large molecules transported through a cell membrane?

Answer 45

through vesicles and vacoules

Question 46

Phagocytosis

Answer 46

cellular eating

Question 47

Pinocytosis

Answer 47

cellular drinking

Question 48

Receptor-mediated endocytosis

Answer 48

when substances enter the cell via inner budding of the plasma membrane

Question 49

Exocytosis

Answer 49

when substances leave the cell