Biology: Cell Transport, Structures, and Photosynthesis Key Concepts

Osmosis

passive transport of water across a membrane (no energy required).

Hypertonic

A solution with a higher concentration of solutes compared to another solution.

Hypotonic

A solution with a lower concentration of solutes compared to another solution.

Isotonic

A solution with an equal concentration of solutes compared to another solution.

Plasma membrane structure

phospholipids with hydrophobic tails & hydrophilic heads.

Functions of plasma membrane

selective permeability, cell connections, regulating entry/exit of substances.

Exocytosis

bulk movement of molecules out of the cell.

Endocytosis

bulk movement of molecules into the cell.

Nucleus

stores DNA, controls activity.

Mitochondria

cellular respiration, ATP production.

Chloroplast

photosynthesis.

Lysosome

digestion, waste removal.

Golgi apparatus

processing/packaging.

ER (smooth & rough)

protein & lipid synthesis.

Cytoskeleton

structural support & movement.

Vacuole

storage, pigments, structural support in plants.

Cell wall

protection & shape in plants.

Energy transformations

potential ↔ kinetic.

Enzymes

protein catalysts that lower activation energy.

Glycolysis

occurs in cytoplasm → produces small ATP & pyruvate.

Cellular respiration steps

Glycolysis → Acetyl-CoA production → Krebs Cycle → Electron Transport Chain.

ATP sources

can come from carbohydrates, fats, and proteins.

Fermentation

occurs under low oxygen; less efficient than aerobic respiration.

Light reactions

capture light → produce ATP & NADPH.

Calvin cycle

uses ATP & NADPH to fix CO2 into glucose.

Photosynthesis equation

6CO2 + 6H2O → C6H12O6 + 6O2.

C3 plants

produce 3-carbon molecule (3PG).

C4 plants

produce 4-carbon intermediate; better in hot/low CO2 environments.

Prokaryotes

no nucleus, no membrane-bound organelles, smaller.

Eukaryotes

have nucleus, organelles, larger.

Autotrophs

make organic molecules from inorganic (e.g., photosynthesis).

Heterotrophs

consume organic material for energy.

How many kcals does the human body use per day

2,200 kcal

What percentage maintains healthy body

75%

What happens to the remaining 25%

Powering physical activities

How many ATP molecules/second r used to power 1 active muscle cell

10,000,000

What is ATP

Adenosine Triphosphate - ENERGY - is required for active transport.

Currency of the cell

Where does glycolysis take place

cytoplasm

Can archea cells run glycolysis

Yes, no mitochondria needed

Does every living organism conduct glycolysis

Yes, no membrane bound cells needed

Anaerobic definition

does not require oxygen

Is glycolysis anaerobic or aerobic?

anaerobic (does not require oxygen)

What is pyruvate?

3 carbon molecule

Anabolic reaction

any chemical reaction that combines simple molecules to build more-complex molecules

Catabolic reaction

any chemical reaction that breaks down complex molecules into simpler molecules

What is the main function of photosynthesis

Provides organic compounds and most of the energy for life on earth. Maintains atmospheric oxygen levels

Steps of the Calvin cycle

Carbon fixation, reduction, release of one molecule of G3P, Regeneration of RuBP.

What is G3P

glyceraldehyde 3-phosphate

What is G3P used for

The synthesis of glucose and starch in chloroplast and to regenerate RuBP

Carbon fixation

CO2+ 5 carbon sugars

Produces 3PG

What is the 3PG molecule?

Phosphoglyceric acid

reduction stage of calvin cycle

Occurs in the Stroma, converts 6 PGA (3C each), 6 ATP, and 6 NADPH to 6 PGAL (3C each), 6 ADP, 6 NADP+, and 6 H2O

Regeneration stage of Calvin cycle

Occurs in the Stroma, converts 5 PGAL, and 3 ATP, to 3 RuBP, and 3 ADP

After 2 turns of the Calvin Cycle, the PGAL that is not regenerated is converted into glucose

Where does the CO2 that enters the Calvin cycle originate from

Atmosphere

Is energy consumed or produced in the Calvin cycle?

consumed

Why must RuBP be regenerated for the Calvin cycle to continue

Essential CO2 fixing molecule

2 reasons why photosynthesis is inefficient at converting light energy into carbs

Rubisco (enzyme that catalyzes carbon fixation) has poor selectivity for CO2 over oxygen

Name of enzyme that performs carbon fixation in Calvin cycle

Rubisco