Lesson 2

Question 1

Robert Hooke

Answer 1

• made many improvements to compound microscopes
• first to see and name “cells”
• published first comprehensive book of microscopy (Micrographia)

Question 2

Cell Theory

Answer 2

1. cells are the building blocks of all plants and animals
2. all cells come from the division of pre-existing cells
3. cells are the smallest unit that perform all vital physiological functions
4. each cell maintains homeostasis at the cellular level

Question 3

why is cell size limited?

Answer 3

surface area to volume ratios

Question 4

somatic cells

Answer 4

body cells, formed by mitosis

Question 5

sex cells

Answer 5

germ cells, reproductive cells

Question 6

ECF

Answer 6

extracellular fluid, includes any fluid outside the cells
- interstitial fluid, blood plasma, lymph, cerebrospinal fluid, etc.

Question 7

cytoplasm

Answer 7

region between the plasma membrane and nucleus

Question 8

cytosol

Answer 8

the clear gel/intercellular fluid within the cytoplasm

Question 9

functions of the plasma membrane (4)

Answer 9

1. physical barrier
2. regulates entry/exit of material into/out of cells
3. responses to changes in the ECF
4. provides support to the cell

Question 10

phospholipids

Answer 10

• 75% of membrane lipids
• amphipathic arrange in a bilayer
• drift laterally, keeping membrane fluid

Question 11

cholesterol

Answer 11

holds phospholipids still and can stiffen membranes

Question 12

glycolipids

Answer 12

phospholipids with short carbohydrate chains on extracellular face; contribute to glycocalyx

Question 13

glycocalyx

Answer 13

carbohydrate component of glycoproteins and glycolipids located external to plasma membrane
- unique in everyone but identical twins

Question 14

functions of the glycocalyx (7)

Answer 14

1. protection
2. immunity to infection
3. defense against cancer
4. transplant compatibility
5. cell adhesion
6. fertilization
7. embryonic development

Question 15

transmembrane proteins

Answer 15

pass completely through the membrane
most are glycoproteins

Question 16

peripheral proteins

Answer 16

adhere to one face of the membrane

Question 17

functions of membrane proteins

Answer 17

receptors, enzymes, channel proteins, carrier, cell-identity markers, cell-adhesion molecules (CAMs)

Question 18

functions of membrane proteins: receptors

Answer 18

bind chemical signals to trigger internal changes, may cause production of a second messenger

Question 19

functions of membrane proteins: enzymes

Answer 19

catalyze reactions including digestion of molecules, production of second messengers

Question 20

functions of membrane proteins: channel proteins

Answer 20

allow hydrophilic solutes and water to pass through the membrane

Question 21

leak channels

Answer 21

channel proteins that are always open

Question 22

gate channels

Answer 22

channel proteins that open only when triggered

Question 23

ligand-gated channels

Answer 23

channel proteins that respond to chemical messengers

Question 24

voltage-gated channels

Answer 24

channel proteins that respond to charge changes

Question 25

mechanically gated channels

Answer 25

channel proteins that respond to physical stress on cells

Question 26

functions of membrane proteins: carriers

Answer 26

bind solutes and transfer them across the membrane

Question 27

pumps

Answer 27

carriers that consume ATP to move substances across the membrane against its concentration gradient

Question 28

functions of membrane proteins: cell-identity markers

Answer 28

glycoproteins act as identification tags

Question 29

functions of membrane proteins: cell-adhesion

Answer 29

mechanically link cells to other cells and to extracellular material

Question 30

osmotic pressure

Answer 30

hydrostatic pressure required to stop osmossis

Question 31

hydrostatic pressure

Answer 31

fluid pressure on the membrane

Question 32

reverse osmosis

Answer 32

process of applying mechanical pressure to override osmotic pressure

Question 33

osmolarity

Answer 33

osmotic concentration; quantity of non-permeating solutes per liter of solution

Question 34

tonicity

Answer 34

ability of a surrounding solution to affect fluid volume and pressure in a cell

Question 35

carrier-mediated transport

Answer 35

proteins in a cell membrane carry solutes into/out of the cell

Question 36

carriers exhibit two main characteristics

Answer 36

specificity and saturation

Question 37

uniport

Answer 37

carrier that moves one type of solute ex. calcium pump

Question 38

symport

Answer 38

carrier that moves two or more solutes simultaneously in the same direction, aka cotransport

Question 39

anitport

Answer 39

carrier that moves two or more solutes in opposite directions, aka countertransport

Question 40

vesicular transport

Answer 40

moves large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles

Question 41

phagocytosis

Answer 41

engulfing and destroying large particles, aka cell eating

Question 42

pinocytosis

Answer 42

taking in droplets of ECF containing molecules useful in the cells, aka cell drinking

Question 43

receptor-mediated endocytosis

Answer 43

particles bind to specific receptors on plasma membrane