Cell Membrane and Transport

Question 1

What was invented when to look at cells?

Answer 1

microscope, late 1600s; recognize Robert Hooke!

Question 2

Cell Theory (three parts)

Answer 2

1. Every organism is made of one or more cells.
2. Cells are the smallest unit of life and have all 7 characteristics of life. (KNOW THESE)
3. Cells come ONLY from preexisting cells.

Question 3

spontaneous generation

Answer 3

false belief that living things arise from non-living material today

Question 4

Pasteur’s swan-neck experiment

Answer 4

proved spontaneous generation incorrect!

Question 5

eukaryotic

Answer 5

has a nucleus; all multicellular and some unicellular organisms are eukaryotic

Question 6

prokaryotic

Answer 6

do not have a nucleus, all unicellular

Question 7

cell membrane structure

Answer 7

phospholipid bilayer – two layers of phospholipids with hydrophobic fatty acid chains and hydrophilic polar group, phosphate, and glycerol

Question 8

other cell membrane parts

Answer 8

proteins (glyco, peripheral, integral, etc.): transport material and have hydrophobic centers so they can float in membrane, can also receive chemical messages
carbohydrates: communication (ID the cell)

Question 9

fluid mosaic model

Answer 9

lipid rafts that float on lipid bilayer

Question 10

selective (semi) permeability

Answer 10

only allowing certain molecules to enter or exit

Question 11

passive transport

Answer 11

movement of molecules from higher concentration to lower concentration; SPONTANEOUS (requires no addition of cellular energy)

Question 12

diffusion

Answer 12

movement of particles from high to low concentration; leads to equilibrium

Question 13

equilibrium

Answer 13

solute concentration becomes equal/balanced

Question 14

dynamic equilibrium

Answer 14

state where overall conditions don’t change but individual parts keep moving

Question 15

concentration gradient

Answer 15

difference in concentration across a space; diffusion goes down this concentration gradient

Question 16

osmosis

Answer 16

diffusion of water across a selectively permeable membrane
WHY: Side with more solute and less water and side with less solute and more water. Side with more water loses water to side with less water because of diffusion.

Question 17

hypotonic

Answer 17

solute is higher in cell, so water moves INTO cell

Question 18

hypertonic

Answer 18

solute is higher outside cell, so water moves OUT OF cell

Question 19

isotonic

Answer 19

equilibrium of solute, so net water movement is 0

Question 20

plasmolysis

Answer 20

cell shrivels up from hypertonic environment

Question 21

turgor pressure

Answer 21

keeps leaves horizontal for best energy capture; plants prefer hypotonic environment because swelling from lots of water causes cell walls to stiffen, causing turgor pressure

Question 22

facilitated diffusion

Answer 22

required for ions and large molecules; uses carrier proteins in membrane to allow diffusion of molecules that can’t regularly pass through

Question 23

glycoproteins and lipids

Answer 23

proteins or lipids in the cell membrane with sugars (carbohydrates) attached to them