Unit 2: Cell Structure and Function (includes most of the questions)

https://askabiologist.asu.edu/cell-viewer-game/play.html <- use that for the diagram labelling of cells

Cell theory

1. All organisms are composed of one or more cells

2. The cell is the basic unit of organization of organisms

3. All cells come from pre-existing cells

Robert Hooke

(1665)
a. observed cork cells
b. coined the term "cell"
c. created the first microscope

Anton Van Leeuwenhoek

(1675)
a. observed living cells
b. created a monocular scope (improved upon Hooke's scope)

Matthias Schleiden

(1830's)
a. observed plant cells
b. concluded that all plants are made of cells

Theodor Schwann

(1830's)
a. observed animal cells
b. concluded that all animals are made of cells

Rudolf Virchow

(1855)
a. concluded that all cells come from other cells

Eukaryotic vs Prokaryotic

Eukaryotic:
a. nucleus
b. membrane bound organelles
(ex: plants, animals, fungi, protists)
Prokaryotic:
a. no nucleus
b. structures not membrane bound
(ex: bacteria)

Multicellular organization

? → subatomic particle → atom/element → compound/molecule →[organelle → cell → tissue → organ → organ system → organism] →population →community → ecosystem → biosphere/earth → solar system →galaxy → nebula → universe → ?

How the membrane regulates transport

being selectively permeable

mitochondria function and role of cristae

→ provides energy by breaking down food molecules with enzymes; high number of mitochondria = more energy available to cell
→ cristae increases the surface area, thus the amount of energy produced and available to the cell

function of the nucleus

control center of the cell; contains DNA, the genetic code for all cell functions

description of turgor pressure

keeps a plant rigid

homeostasis

maintenance of a stable internal environment in a changing external environment ex: dog panting; sweating

consequences of an unstable internal environment

wastes build up, food runs out, foreign substances like pathogens (bacteria, viruses, parasites) invade

how a cell membrane’s selective permeability achieves homeostasis

The cell membrane’s selective permeability chooses what goes in/out of a cell and regulates transport

phospholipid parts

Phosphate, glycerol, fatty acid tails (stacked in that order)

how the attraction/lack thereof to water determines how a cell membrane is structured

Water forces the structure of the lipid bilayer since the phosphate is hydrophilic and the fatty acid tails are hydrophobic

how a cell membrane is a fluid mosaic

the membrane is like a fluid, enabling phospholipids and proteins to move about

diffusion

net movement of particles from an area of HIGH concentration to an area of LOW concentration ex: the perfume spray, opening soda bottles and CO2 diffusing in the air, odors from food, air pollution

how dynamic equilibrium is acheived

when there is still constant (random) motion of particles, but no overall difference in concentration; particles are evenly dispersed across a given space

osmosis

diffusion of water from an area of high concentration to an area of low concentration

diffusion vs osmosis

Both processes involved a movement from high to low concentration areas. Diffusion is the movement of particles but osmosis a specific kind of diffusion for water

isotonic vs hypotonic vs hypertonic

Isotonic: same concentration of particles in the solution in/out of the cell
Hypotonic: concentration of particles in the solution is LOWER than inside the cell
Hypertonic: Concentration of particles in the solution is higher than inside the cell

consequences of hypotonic and hypertonic solutions

Hypotonic: cytolysis (cell bursts from water moving in)
Hypertonic: Plasmolysis (cell shrivels from water moving out)

passive vs active transport

Passive: high to low; diffusion of materials across membrane along gradient without energy
Active: low to high; diffusion of materials across membrane against gradient with energy

Endocytosis and exocytosis

Endo: into cell
Exo: Out cell

Phagocytosis vs pinocytosis

Phagocytosis: solid material
Pinocytosis: fluid material

Why it’s advantageous for a cell to be small

→ metabolically efficient/ability to utilize energy to synthesize proteins; larger cells have a decreased surface area to volume ratio; a cell would need to support and increasing volume with a shrinking boundary, decreasing the metabolic activity of the cell

Ways for surface area to volume ratios to be improved/increased

→ make cells smaller
→ complicate the cell (fold it)