Biology Test 5: Photosynthesis & Cellular Respiration

What are the two products of the light reactions that are needed for the Calvin Cycle?

NADPH and ATP

What is the pigment in chloroplasts that performs photosynthesis?

chlorophyll

Glucose is a ...

sugar, carbohydrate, source of quick energy

raw materials for Photosynthesis

water and carbon dioxide

role of NADPH in cellular respiration

function as a high energy electron carrier

Glucose is broken down into pyruvic acid during...

Glycolysis

What are the outputs of the Kreb's cycle

4 CO2, 6 NADH, 2 FADH2, 2 acetyl- CoA

The splitting of the glucose molecule is called?

Glycolysis

Each glucose (6C) produces how many pyruvic acid (3C) molecules?

2

What are the reactants (taken into) of cellular respiration?

Oxygen and glucose

This process releases chemical energy from sugars and other carbon-based molecules to make ATP when oxygen is present.

cellular respiration

What happens in the electron transport chain?

NADH and FADH2 drop off hydrogens to form massive amounts of ATP

Where does the Krebs Cycle take place?

mitochondria

Why does the third phosphate in ATP have so much energy stored in the bond?

it is highly unstable

original source of energy

is light from the sun

autotrophs

organisms that use light energy to build organic molecule from inorganic substance

examples of autotrophs

plants, algae, some unicellular organisms

heterotrophs

animals and other organisms that can't make their own food

examples of heterotrophs

animals, fungus, some unicellular organism

biochemical pathway

a complex series of reactions that perform a specific function

photosynthesis equation

6CO2 + 6H2O + light energy --> C6H12O6 + 6O2

cellular respiration equaiton

C6H1206 + 6O2 --> 6CO2 + 6H2O + energy

ATPase

an enzyme that breaks ATP down to ADP

Structure of Chloroplasts

outer membrane, inner membrane, Thylakoid w/ chlorophyll, grana, & stroma

Chlorophyll

Green pigment in plants that absorbs light energy used to carry out photosynthesis

Chlorophyll a

absorbs more blue light

Chlorophyll b

absorbs more red light

Cartenoids

includes yellow, orange, & brown pigments; allows plant to absorb more of the sun's energy

2 parts of photosynthesis

light dependent and light independent

Light dependent Reactions

Occurs in Thylakoid (membrane), converts light energy to chemical energy (ATP)

Photosystems I & II

clusters of pigments arranged in the thylakoid

stages of light dependent reactions

1: light energy is absorbed, electrons are energized, water is split
2: H+ concentration is high and diffuse across thylakoid membrane, movement triggers formation of ATP (phosphorylation)

Phosphorylation

when a P is bonded with ADP, making ATP

Process of light dependent reactions

1. light enters the leaf & is absorbed by the photosystems
2. Water is taken into the leaf & "split" in PS2
equation: 2(H2O) ==> 4(H+) + 4(e-) + O2
3. oxygen that came from the breakdown of water is released into the atmosphere (function of oxygen is for cellular respiration)
4. electrons in the chlorophyll molecules absorb the energy (source of electrons is water)
5. as electrons are passed along (by the electron transport chain), the energy is released to form NADPH

Inputs of Light dependent reactions

H2O & Light

Outputs of Light dependent reactions

O2, NADPH, & ATP

Stomata

microscopic openings in the epidermis of the leaf

Transpiration

process by which water vapor leaves the plant through the stomata in the leaves

Light Independent Reactions

AKA: Calvin-Benson cycle, Calvin cycle; occurs in the stroma, carbon fixation

Stroma

fluid portion of the chloroplast; outside of the thylakoids

Carbon fixaton

carbon atoms from CO2 are bonded into organic compounds (sugars)

process of light independent reactions (the Calvin Cycle)

1. an enzyme combine CO2 with RuBP and results in the formation of PGA
2. PGA receives a phosphate from ATP and a proton from NADPH which results in ADP & NADP+ (these are then recycled)
3. The resulting PGAL are either used:
-by the plant cell to make other organic compounds (one of the 6 molecules of PGAL is transferred to the cytoplasms and used in the synthesis of sugars & and other carbs)
-to regenerate the 5 carbon compound from step 1: RuBP (requires more ATP)

RuBP

a five-carbon carbohydrate

PGA

a six-carbon molecule that splits into a pair of 3 carbon molecules; pair of 3 carbon molecules

Inputs of light independent reactions/ Calvin cycle

NADPH, ATP, CO2

Outputs of light independent reactions/calvin cycle

sugars

White light

all colors of the rainbow

Best light color to absorb in plants

blue & red

Worst light color to absorb in plants

green (it's going to be reflected so no light is absorbed)

Environmental Factors that affect photosynthesis

light intensity, carbon dioxide, amount of water, temperature, humidity, oxygen

Stages of Cellular Respiration

glycolysis, krebs cycle (citric acid cycle), electron transport chain

aerobic

requires oxygen to be present to complete reaction (reactants are glucose and oxygen)

anaerobic

no oxygen it required (reactant is glucose)

glycolysis

the process by which glucose is concerted to pyruvic acid (occurs in the cytoplasm, anaerobic, uses 2 ATP to produce 4 ATP & 2 pyruvic acids, but there is a NET GAIN of 2 ATP & 2 pyruvic acid)

oxidize

loses electron

process of Glycolysis

1. glucose is converted into a 6-carbon chain, used 2 ATP which became 2 ADP
2. carbon chain is split into 2 molecules of PGAL
3. PGAL is oxidized to make two 3-carbon chain molecules
4. the carbon molecule are then concerted into 2 molecules of pyruvic acid, 4 ATP are formed

inputs of glycolysis

Glucose and 2 ATP

outputs of glycolysis

2 pyruvate, 2 ATP(net gain)

where does the pyruvate go?

1. pyruvic acid moves from the cytoplasm to the mitochondria
2. gives off a CO2 and combines with an enzyme (coenzyme A) to form acetyl-CoA

Krebs cycle

in the presence of oxygen the acetyl-CoA will go through the citric acid cycle, where it will go through a series of reactions (occurs in the mitochondria, breaks down acetyl-CoA and form ATP and CO2, electrons carriers -NAD+ & FAD- take electrons to the electron transport chain)

Outputs of Krebs Cycle

4 CO2, 2 acetyl-CoA, 6NADH, 2 FADH2

Steps of Electron Transport Chain

1. NADH & FADH₂ give up electrons that pass through the membrane from protein to protein (slowly releases energy at each stop; releases H⁺)
2. Some of the energy is used to form ATP, some is used to pump ions of H⁺ into the mitochondrion (creates a gradient that provides the energy for ATP production)
3. Final electron acceptor is oxygen (reacts with 4H and 4 electrons to form 2H₂)
4. Total of 32 ATP are made

Inputs of Electron Transport Chain

electrons from NADH & FADH₂, oxygen

Outputs of Electron Transport Chain

2H₂0, 32 ATP

lactic acid fermentation (anaerobic)

1. 2 Pyruvic acid + NADH → 2 Lactic Acid + NAD⁺
2. NAD⁺ returns to glycolysis to form ATP
3. Lactic acid eventually goes back to pyruvic acid when transferred from the muscle cells to the liver.
4. Results in muscle fatigue

Acoholic Fermentation (anaerobic)

1. CO2 removed from pyruvic acid leaving a 2 carbon compound
2. NADH + H+ are added to the 2 carbon compound to form ethyl alcohol (regenerates NAD+ for glycolysis = 2 ATP)

Photosynthesis

Food synthesized
Energy from sun stored as glucose
Carbon dioxide taken in
Oxygen given off
Produces sugars from PGAL
Requires Light
Occurs only in presence of chlorophyll

cellular respiration

Food broken down
Energy of glucose released
Carbon dioxide is given off
Oxygen is taken in
Produces CO and HO
Does not require light
Occurs in all living cells