Lecture 8 - cellular respiration Flashcards
What cells do photosynthesis?
Plants
What cells do cellular respiration?
Plants and animals
In context to energy, what do all eukaryotes have?
All eukaryotes have organelles that are responsible for converting an external energy into a usable form.
What is ATP?
ATP is an energy carrier.
What is the structure of ATP?
A triphosphate group, ribose and adenine
How does ATP create energy?
Due to a reaction where the triphosphate group releases a phosphate to become diphosphate. When this bond breaks, energy is released.
What does the cell need energy for?
For mechanical work
To make new materials
For transport
To maintain order
What is the mitochondria?
The mitochondria is the site of cellular respiration.
What determines number of mitochondria in a cell
The amount of energy that is required for the cell.
Eg. Muscle cells need more mitochondria
What does mitochondria contain and what does it mean for the mitochondria?
Mitochondrial DNA and ribosomes.
This means they can produce some but not all mitochondrial proteins
Describe the structure of the mitochondrion.
The mitochondria and has two membranes (the inner and outer mitochondrial membranes) and the mitochondrial matrix which is inside the inner membrane.
Describe the inner membrane
The inner membrane is made of highly folded cristae which provides a bigger surface area for activity.
Describe the intermembrane space
This is the space between the two membranes
Describe the mitochondrial matrix
The space between the inner membrane. Equivalent to the cytosol of the cell.
What are the three stages of cellular respiration?
1) Glycolysis
2) Pyruvate oxidation and citric acid cycle
3) oxidative phosphorylation
Describe what happens in stage one of cellular respiration
In the cytosol sugar-glucose is converted into a smaller molecule pyruvate. This reaction generates 2ATP and releases two electrons which are transferred to the high energy electron carrier -NAD+ making it NADH.
Describe stage two of cellular respiration
Stage two happens in the mitochondrial matrix and pyruvate is converted into Acetyl CoA (+CO2). As we do that we extract more high energy electrons( 2NADH)
The Acetyl CoA then enters the citric acid cycle. As a result we produce 2ATP, more high energy electrons (NADH) and another high energy electron accepting molecule FADH2 (+2CO2)
Summarise stages one and two of cellular respiration
We start with glucose and we end up with ATP and some NADH and FADH2
Compare NADH to FADH2
FADH2 is similar to NADH but it has a little bit less energy in it
Describe stage three of cellular respiration
Stage three happens in the inner membrane of the mitochondrion and occurs in two parts:
Part 1 - electron transport (electrons from NADH and FADH2)
Part 2 - Chemiosmosis (ATP production)
Describe part one of stage three of cellular respiration.
In part 1 the movement of electrons allow for a proton gradient to be established.
Describe the electron transport chain.
The electron carriers (NADH and FADH2) shuttle high energy electrons to the end of mitochondrial membrane. These electrons then move through protein complexes embedded in the inner membrane. As these electrons move, protons (H+) are pumped across the membrane into the into membrane space.
Describe how the proton gradient and cellular respiration is generated.
Due to the electron transport chain, protons accumulate in the innermembrane space. This makes the protein concentration on either side of the inner mitochondrial membrane different, creating a proton gradient. This gradient then leads into part 2 of stage 3 in cellular respiration.
Describe part two of stage three of cellular respiration
In part 2 the proton gradient established in part 1 allows for chemiosmosis to occur.
Describe chemiosmosis
The inner mitochondrial membrane contains the protein complex ATP synthase. This complex spans the membrane from the inner membrane space in the mitochondrial matrix. ATP synthase converts ADP + Pi into ATP and the established proton gradient powers this process to occur.
Summarise cellular respiration
Chemical energy is converted from one form to another. From glucose to ATP.
The structure of the mitochondrion enables the protein gradient to be established across the inner membrane and this drives the production of ATP
What is consumed in cellular respiration?
Glucose and oxygen
What is produced in cellular respiration?
Carbon dioxide, water and ATP
What does ATP power?
Cellular activity
What does ATP enable
The controlled release of energy.
