U2: Metabolic Processes (SBI4U)

Unit 2

Metabolic Pathways

Anabolism

building larger molecules from smaller ones (EX. Building Muscle)

Catabolism

breaking down molecules into simpler products (EX. Cellular Respiration)

Metabolic Pathways

Many reactions that happen consecutively, includes many intermediates

Intermediates

Substances created in one reaction and used up immediately in another (EX. Pyruvate from glycolysis and used up immediately in link chain for Acetyl CoA)

Endergonic reactions

Reactions that requires energy to be absorbed to be able to take place (Photosynthesis)

Exergonic reactions

Reactions that release energy (Cellular Respiration)

What is the chemical formula of cellular respiration

Glucose + Oxygen = Carbon Dioxide + Water

C6H12O6 + 6O = 6CO2 + 6H2O

Where does Glycolysis occur

The cytoplasm

Is Glycolysis anaerobic or aerobic

Anaerobic (no oxygen required)

Glycolysis is a 10 step reaction the converts ______________ into two ________________ molecules

6 carbon glucose

3 carbon pyruvate

Glycolysis produces 4 _______ molecules (stage 7 & 10) but uses 2 _______ molecules (stage 1 & 3)

ATP

Glycolysis produces 2 ________ (stage 6) that will produce 3 ______ in the ETC

NADH

ATP

NAD+ is an electron carrier that is reduced to ________

NADH

NAD+ gains an ______ ion and two _______________ become NADH What type of reaction is this?

H+

electrons

Redox or oxidation-reduction reaction

Glycolysis: at stage 4-5 the 6 carbon glucose splits to from two _________

G3P

At stage 9 two ____________ molecules are removed

water

2 ___________ is produced at the end of glycolysis

Pyruvate

After the creation of pyruvate there are two possible pathways:

1. oxygen is present the _________ __________ _________ will occur

2.oxygen is not present, _______________ will occur

Citric Acid Cycle

Fermentation

Alcoholic fermentation

Produces ethanol and carbon dioxide in single celled organisms

NADH is oxidized back to NAD+

Produces 2 ATP

lactic acid fermentation

Produces Lactic acid in multicellular organisms (Causes cramping)

NADH is oxidized back to NAD+

Produces 2 ATP

Link Reaction

2 Pyruvate is converted to 3 Acetyl CoA by releasing CO2

An NADH for each pyruvate is made (2 NADH total)

Krebs cycle: FAD+ is reduced to ________ by gaining two _______ ions and two ______________

FADH2

H+

Electrons

Acetyl CoA enters the ________ ________ a 9 step process

Krebs cycle

Krebs cycle: For the 2 Acetyl CoA 4 _____, 6 ______, 2 ______, and 2 _______ molecules are produced

4 CO2

6 NADH

2 FADH

2 ATP

_______ is released at steps 4 and 5

________ is created at steps 4, 5, and 9

______ is created at step 6

________ is created at step 7

_______ is used up in step 8,

CO2 steps 4 and 5

NADH steps 4,5 and 9

ATP step 6

FADH2 steps 7

H2O steps 8

The ETC puts the electrons gained by ________ and _______ to work by driving protein pump channels

NAD+

FAD+

At the end of the ETC __________ _______ accepts 4 electrons and 4 H+ ions to produced 2H20

Oxygen gas

Electrons are lost by NADH and FADH2 and are passed through 6 channels and carrier proteins called _______________

Cytochromes

Cytochromes are embedded in the ________ _____________ of the mitochondrion and are known as complex I, complex II, coenzyme Q, complex III, cytochrome C, and complex IV

Inner membrane

Most ATP formed in the ETC is through ______________ ___________________ whereas the ATP produced in glycolysis and the Krebs Cycle was through

______________-_________ _________________

oxidative phosphorylation

substrate-level phosphorylation

Oxidative phosphorylation is the process that couples the oxidation of ___________ and __________ with the synthesis of _______ from ________

NADH and FADH2

ATP from ADP

the H+ gradient that is created is used by ______ ____________ to make ATP by ____________________

ATP synthase

Chemiosmosis

in the ETC, NADH is oxidized at complex ___ and FADH2 is oxidized at complex ___

complex I

complex II

The passage of ______ ions through ATP synthase and into the inner mitochondrial membrane provides the energy to phosphorylate ______ to ______

H+ ions

ADP to ATP

ATP yield

10 NADH: ____ ATP

2 FADH2: ____ ATP

Glycolysis: ____ ATP

Krebs cycle: ____ ATP

TOTAL YEILD (38 ATP)

10 NADH: 30 ATP

2 FADH2: 4 ATP

Glycolysis: 2 ATP

Krebs cycle: 2 ATP

where is phosphofructokinase used (2 places) and what is its function?

Used in Glycolysis and Krebs cycle when there is too much ATP, binds to allosteric site for ATP rendering it inactive

Is photosynthesis endergonic or exergonic? Anabolic or catabolic?

Endergonic

Anabolic

The light-dependent reactions uses ___________ and ____________ to produce ______________ and ______________ is released as a byproduct

Uses sunlight and water

Produces ATP and NADPH

Oxygen gas

The light-independent reaction uses _______ and __________ to produce _____________ and __________ ___________

Uses ATP and NADPH

Produces glucose and carbon dioxide

Photosynthesis occurs in?

chloroplast

Carbon dioxide enters the leave through what?

The stomata

The stomata are usually open during the _______ and closed during the _________

Day

Night

Water enters through the roots and is transported to the leaves via what?

The xylem

What is the main pigment in plants that absorbs light energy.

Chlorophyll

Where is chlorophyll located?

Thylakoids

Thylakoids are flattened interconnected disks that are stacked into structures called what?

Grana

surrounding the grana is a fluid-filled interior called the _________ it contains many enzymes needed for photosynthesis

Stroma

Chlorophyll absorbs _______ and ______ light and reflects ________ and ___________ light.

Red and Blue

Green and Yellow

There are two photosystems ___ and _____

I and II

Antenna chlorophyll gather light energy and funnel it to on chlorophyll called what?

The reaction center

Where does PSII get another electron from when it becomes positively charged and how?

From a water molecule with help from a water-splitting enzyme

How many times is this process done to from one oxygen gas molecule?

Four times

H+ ions remain in the __________ ____________ to be used later by the ______ ______________ proton pump

Thylakoid space

ATP synthase

PSII transfers the electrons one by to the the _________________ ______ ________________

Cytochrome b6-f complex

The cytochrome b6-f complex uses the released energy to pump more H+ ions from the _____________ into the ________________ ____________

Stroma into the thylakoid space (creates concentration gradient)

In the meantime PSI absorbs __________ ___________ and excites an _______________,

Light energy

Electron

At the end of PSI ________ is reduced to _________ by receiving an electron

NADP+ reduced to NADPH

ATP synthase pump H+ ions from the __________ ________ to the _________

Thylakoid space to the stroma

What is non-cyclic photophosphorylation?

Light is the original source of energy to create ATP

What is cyclic photophosphorylation?

Energy from chloroplasts producing more ATP if needed, instead of NADP+ receiving the last electron it is cycled back to the b6-f complex to produce more H+ ions

In the light independent reaction plants use the _______ and __________ created in the previous reaction to convert carbon dioxide into carbohydrates

ATP and NADPH

This anabolic reaction does not require __________ and can happen at any time.

Light

Calvin's cycle: six molecules of carbon dioxide produce two molecules of _________

G3P

The Calvin Cycle occurs in the __________

Stroma

The calvin cycle is divided into 3 phases: __________ ___________,_____________, _______ _______________

Carbon fixation, Reduction, RuBP regeneration

In the carbon fixation phase CO2 from the air is attached to the five-carbon molecule __________

RuBP

The six-carbon molecule is unstable and splits into two ________ molecules

PGA

The six-carbon RuBP is catalyzed by the _____________ enzyme

RuBisCO

In the reduction phase ________ and ____________ are used to create higher energy G3P molecules

ATP and NADPH

Two molecules of G3P are used to make six carbon __________ while the other ten G3P molecules are recycled in the regeneration of RuBP phase

Glucose

the Calvin Cycle must be completed ___ times to create one ___________ molecule

6

glucose

18 ATP in total (12 ATP for G3P and 6 ATP for RuBP) and 12 ________ must be used to create glucose

NADPH

6 ______ are also created in the reduction phase

H2O

The calvin cycle happens in _____ plants which constitute almost 90% of the plants on Earth

C3

RuBisCO is an essential enzyme for photosynthesis however it also has a binding site for _____________

Oxygen

___________ __________ and __________ complete for the same RUBisCO active site thereby reducing the efficiency of photosynthesis

Carbon dioxide

Oxygen

when oxygen reacts with RuBP it goes through another metabolic process called what?

Photorespiration

Plants that live in _____ and _____ conditions have evolved to reduce the amount of photorespiration

Hot and dry

There are two types of these plants ____ and ______ plants

C4 and CAM

C4 plants are able to pump and trap CO2 in specialized mesophyll cells with the help of the enzyme ______ _____________ this then makes it easier for RuBisCO to bond to ______ rather than ____

PEP carboxylase

CO2

O2

the Calvin Cycle then occurs in another type of cell the ________ ________ cell

Bundle sheath

In CAM plants _________ _________ only happens at night when the stomata can open to prevent water loss

Carbon fixation

Once the CO2 is fixed it is stored in large ___________ until daytime arrives for the light dependent reaction

Vacuoles