Chapter 8: Dynamic Cells

Question 1

what are the major elements in cells?

Answer 1

• carbon
• hydrogen
• oxygen
• nitrogen

Question 2

what are the organic compounds in cells?

Answer 2

• lipids
• carbohydrates
• proteins
• nucleic acid

Question 3

what is a MAJOR compound in both plants and animal cells?

Answer 3

water, solvent for all biological reactions

Question 4

trace elements?

Answer 4

are substances that are found in small amounts for the cell’s health, example: Mg, Zn, Mn, Fe

Question 5

what does the cell membrance?

Answer 5

important for maintaining equilibrium inside cell

Question 6

what is selectively permeable?

Answer 6

allows some cells to pass and keeps away other non-wanted cells

Question 7

what does the membrane consist of?

Answer 7

phospholipid bilayer

Question 8

what are suspended in the phospholipid bilayer?

Answer 8

proteins are suspended in:
- out or in the membrane
- some run through the membrane
- some proteins are suspended on the surface with glycoproteins on it

Question 9

what are some particles that can enter/exit the membrane?

Answer 9

• ions
• molecules
• mirco-organisms

Question 10

what is brownian motion?

Answer 10

particles are in a constant and random motion. helps with transportation

Question 11

what is concentration gradient?

Answer 11

moles move from high to low concentration, follows the flow to move past the membrane

Question 12

what is equilibrium?

Answer 12

when molecules are equally distributed on both sides of the membrane

Question 13

what is passive transports?

Answer 13

the movement of cells following concentration gradient without energy (ATP)

Question 14

types of passive transportation

Answer 14

• diffusion
• facilitated diffusion
• osmosis
  all moves with concentration gradient without energy

Question 15

what is simple diffusion ?

Answer 15

particles move down the concentration gradient to reach equilibrium (from high concentration to low)

Question 16

what is facilitated diffusion?

Answer 16

use of transport proteins to help particles with diffusion across the membrane, used for molecules too big or charged

Question 17

what is osmosis?

Answer 17

when highly solvent particles move from semi-permeable membrane in order to be diluted by water

Question 18

types of facilitated diffusion

Answer 18

• carrier proteins: transports large molecules in changing its shape
• channel proteins: transports charged molecules in a tunnel like pore

Question 19

hypotonic ?

Answer 19

more water, less solvent (swells)

Question 20

hypertonic?

Answer 20

more solvent, less of water (shrink)

Question 21

isotonic ?

Answer 21

equal concentration

Question 22

what causes rate of diffusion to be higher?

Answer 22

• added heat
• increased movement in molecules

Question 23

what is active transport?

Answer 23

uses energy (ATP) to move molecules against the current and could use protein carriers (moves from low to high)

Question 24

reasons why cells use active transportation?

Answer 24

• plant cells root take in minerals from surround soils
• animals cells remove waste

Question 25

what is endocytosis?

Answer 25

takes in materials or fluids inside the membrane

Question 26

types endocytosis?

Answer 26

a) phagocytosis: eats materials and foods b) pinocytosis: drinks fluid and water c) receptor-mediated: receptor protrudes out of the membrane and detects specific molecules (take in molecules such as cholesterol)

Question 27

what is exocytosis?

Answer 27

allows materials stored in vesicles and vacuoles to exit cell (fuses with membrane and stored contents are released)

Question 28

what is a unicellular ?

Answer 28

single cells that are more efficient, but takes time to absorb the nutrients

Question 29

what is particle diffusion?

Answer 29

NO ENEGRY NEEDED once substance is inside the cell, rate of diffusion is slow and inefficient due to the weak pull

Question 30

why are larger cells inefficient?

Answer 30

the larger cell, the more space there is that a particle needs to go to a certain area ( less efficient at getting nutrients)

Question 31

surface area to volume ratio

Answer 31

surface area = cell membrane volume = cell contents

Question 32

why does surface area to volume ratio relate with diffusion rate?

Answer 32

rate of diffusion depends on the surface area to volume ratio - smaller cells have bigger surface area and less volume meaning it more efficient in exchanging material unlike the larger cells

Question 33

why do cells divide?

Answer 33

cells grow faster in volume than surface area causing them to divide

Question 34

why are larger cells bad?

Answer 34

larger cells have a lower surface area to volume ratio, causing them to be starved or poisoned (limits growing)

Question 35

why are multicellular organisms better?

Answer 35

divides up life functions and having a higher rate of survival than unicellular due to cell division (can also increase in size without a limit)