A+P 1.3 Organization of cells

Question 1

Name the three main parts of a cell

Answer 1

plasma membrane, cytoplasm, nucleus

Question 2

DESCRIBE the plasma membrane

Answer 2

• plasma membrane : flexible outer surface; regulates flow of materials into and out of cell; plays key role in communication among and between cells and external environment

Question 3

DESCRIBE cytoplasm

Answer 3

• consists of all the cellular contents between the plasma membrane and the nucleus
• divided into two components; cytosol and organelles

Question 4

DESCRIBE cytosol and organelles

Answer 4

• cytosol : liquid portion of cytoplasm; consists mainly of water with dissolved solutes particles
• organelles : found within the cytosol; membrane-bound structures with specific structures and functions

Question 5

DESCRIBE the nucleus

Answer 5

• the largest organelle of a cell
• acts as the control center of the cell because it contains the organisms genes the control cell structure and activities

Question 6

DEFINE the function of the plasma membrane

Answer 6

• flexible, sturdy barrier consisting mainly of lipids and proteins
• Lipid bilayer : two tail-to-tail layers made up of three types of lipids: phospholipids, cholesterol, glycolipids
• two types of membrane proteins
  
  • integral; extend into or through the lipid bilayer
  • peripheral; loosely attached to the interior or exterior surface of the membrane; glycoproteins are peripheral proteins attached to carbohydrates

Question 7

Cell membrane function

Selective Permeability

Answer 7

• allows some substances to move into and out of the cell but restricts others

Question 8

cell membrane function of

lipid portion

Answer 8

• permeable to water and nonpolar lipid soluble molecules

Question 9

membrane function of integral proteins

Answer 9

may form ion channels through which ions such at potassium(K+) can move into and out of cells

Question 10

membrane function of other proteins

Answer 10

act as carriers which change shape as they move a substance from one side to another

Question 11

membrane function

large molecules

Answer 11

unable to pass through the plasma membrane except by transport within vesicles

Question 12

membrane function

integral proteins - receptors

Answer 12

recognize and bind specific molecules; some integral proteins are enzymes speeding up specific reactions

Question 13

membrane function

glycoproteins and glycolipids

Answer 13

often serve as identity markers to recognize its own growing tissues or respond to dangerous outside cells

Question 14

transport across the plasma membrane

Answer 14

• movement of materials across the plasma membrane is essential to the life of a cell
• substances move into the cells to support metabolic reactions
• cells produce waste and must be moved out of the cell

Question 15

Intracellular Fluid (ICF)

Answer 15

• fluid found inside body cells

- makes up about 2/3 of the fluid found in the body

Question 16

Extracellular Fluid (ECF)

Answer 16

• fluid outside of the cell
  
  • between cells = interstitial
  • in blood vessels = plasma
  • in lymphatic vessels = lymph

Question 17

Define solute

Answer 17

material dissolved in a fluid

Question 18

define concentration

Answer 18

amount of solute dissolved in a solvent

Question 19

define concentration gradient

Answer 19

the difference between high and low concentration

Question 20

DEFINE passive transport

Answer 20

kinetic energy moves molecules from areas of high concentration to low concentration ; simply diffusion

Question 21

DEFINE active transport

Answer 21

cellular energy (ATP) is used to push the substance against the concentration gradient ; from low to high

Question 22

EXPLAIN passive transport

Answer 22

• involves only kinetic enery (energy of motion) ; does not require ATP
• ex. simple diffusion, facilitated transport, osmosis

Question 23

EXPLAIN Simple diffusion

Answer 23

• movement of a substance through the lipid bilayer, from an area of high concentration to low until equilibrium is reached
• pass through lipid bilayer if lipid-soluble; oxygen, carbon dioxide, fatty acids, steroids
• polar molecules such as water and urea also pass through

Question 24

EXPLAIN facilitated diffusion

Answer 24

• some molecules bind to integral proteins on one side of the membrane and are released on the other side after the protein carrier undergoes a change in shape

Question 25

Ion channels

Answer 25

ion channels in the membrane allow specific ions to pass through

Question 26

Osmosis

Answer 26

- diffusion of water from an area of higher concentration to lower

Question 27

isotonic solution

Answer 27

- concentration of water and solute is the same on both sides of membrane - water enters and leaves cell at the same rate - cell maintains normal shape

Question 28

Hypotonic solution

Answer 28

- low concentration of solute, high concentration of water outside the cell in ECF - water enters the cell at a faster rate than it leaves - the swells or ruptures (hemolysis)

Question 29

Hypertonic solution

Answer 29

- high concentration of solute and low concentration of water outside cell in ECF - water leaves the cell at a faster rate than it enters - cell shrinks (crenation)

Question 30

Two types of active transport

Answer 30

- pumps involving carrier proteins | - transport within vesicles

Question 31

Major/most important pump for active transport

Answer 31

- sodium-potassium pump; critical for nerve and muscle function

Question 32

Methods transport in vesicles

Answer 32

- Endocytosis - phagocytosis - bulk phase endocytosis - Exocytosis

Question 33

Endocytosis

Answer 33

- substances are surrounded and enclosed by a piece of the plasma membrane - this forms a vesicle that is brought into cell

Question 34

two types of endocytosis

Answer 34

- phagocytosis "cell eating" large plasma membrane projections called pseudopods surrounds and ingest bacteria and other foreign particles - bulk phase endocytosis "cell drinking" ingestion of tiny droplets of ECF (pinocytosis)

Question 35

Exocytosis

Answer 35

moving substances out of a cell by fusing vesicle membrane with plasma membrane resulting in excretion into ECF

Question 36

Nucleus

Answer 36

- spherical or oval structure | - surrounded by nuclear envelops with nuclear pores

Question 37

Nuclear pores

Answer 37

small openings in the nuclear envelope which control movement in and out of the nucleus

Question 38

nucleolus

Answer 38

structure of the nucleus that makes ribosomes that pass into cytoplasm through nuclear pores

Question 39

somatic (body) cells

Answer 39

- 46 chromosomes | - 23 from each parent

Question 40

genome

Answer 40

the total genetic information carried in a cell or organism

Question 41

Average human adult | cell number and type

Answer 41

composed of nearly 100 trillion cells consisting of about 200 different cell types

Question 42

cell measurements

Answer 42

- measured in micro meters (1/1000 meter)

Question 43

oocyte

Answer 43

- largest cell | - diameter of about 140 micrometer; barely visible to the unaided eye

Question 44

Red blood cells

Answer 44

- diameter of 8 micrometer

Question 45

shapes of cells

Answer 45

- round, oval, flat, cube-shaped, column-shaped, elongated, star-shaped, cylindrical, or disk-shaped

Question 46

sperm cell shape

Answer 46

-has a long whip like tail (flagellum) that it uses for motion

Question 47

red blood cell shape

Answer 47

- disk shape | - the large surface are enhances its ability to pass Oxygen to other cells