Unit 2 - Cell Respiration Flashcards
Describe the structure of the ATP molecule
ATP stands for adenosine triphosphate
It contains ribose sugar, a nitrogenous base (adenine), and phosphate
Definitions
Extracellular fluid
The liquid environment outside of the cell
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Solution
A mixture of solute and solvent
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Homeostasis
The maintenance of constant conditions
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Define diffusion. What factors affect it?
The movement of material into/out of a cell down a concentration gradeint (high to low)
Temperature: An increase in temperature increases the speed at which molecules move at.
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Osmosis
Diffusion of water across a living membrane
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Both diffusion and osmosis want to achieve an…
Isotonic solution, in which the ICF and ECF have the same solute and water concentration
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Hypertonic solution
The ECF has a higher solute (therefore less water) concentration than ICF
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Hypotonic solution
The ECF has a lower solute concentration (therefore more water) than the ICF
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Facilitated diffusion
Diffusion aided by channels or carriers (proteins)
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Passive transport
Movement from high to low concetration
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Active transport
Movement from low to high concentration, requiring ATP
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Endocytosis
Entry of material into the cell
Endocytosis
Pinocytosis
Cell drinking
Endocytosis
Phagocytosis
Cell eating
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Exocytosis
Removal of waste products of water from the cell
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Plasmolysis
The shrinking of the cytoplasm away from the cell wall due to a hypertonic situation (plant)
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Crenation
The shrinkage of cells due to a hypertonic situation (animal)
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Turgor pressure
The pressure of water pushing the cell membrane against the cell wall due to a hypotonic situation (plant cells - this is ideal)
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Cytolysis
Cell bursting due to a hypotonic situation (animal)
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Fluid Mosaic Model
The model of the cell membrane
Compare substrate level phosphorylation with oxidative phosphorylation
Substrate-level phosphorylation is directly phosphorylating ADP with a phosphate and energy to create ATP.
Oxidative phosphorylation is when ATP is generated from the oxidation of NADH and FADH2 and the subsequent transfer of electrons and pumping of protons.
What is the difference between an electron carrier and a terminal electron acceptor?
An electron carrier is first oxidized and then reduced, while a terminal electron acceptor is only reduced—a terminal electron acceptor is at the end of an electron transport chain
Describe the 4 components of the cell membrane
- Main component: phospholipid bilayer
- Isolates ECF from ICF
- 2nd component: proteins
- Regulates movement of materials
- Used for communication
- 3rd component: glycolipids and glycoproteins; the carbohydrate complex
- Used for communication (carbon chain attached)
- 4th component: cholesterol
- Keeps the shape of the membrane
State the equation for cellular respiration (aerobic) and photosynthesis
State the 4 types of proteins in the membrane
- Transport proteins (a channel or a carrier)
- Recognition proteins (identifies cell; an antigen is an example)
- Receptor proteins (metabolism behaviour, message receiver)
- Adhesion proteins (leak-proofing, communication)
State the 5 parts of the mitochondria
- Outer mitochondrial membrane
- Inner mitochondrial membrane
- Inter-membrane space/compartment
- Matrix
- Cristae (inner folds that increase SA to benefit the electron transport system)
What is the sodium-potassium pump?
- An “electrogenic pump” (electric potential) found in animals
- Found within membranes
- Function: get rid of 3 Na+ and take in 2 K+
- Pump gets its energy from chemical energy in which ATP is hydrolyzed
What is the hydrogen-potassium pump?
- Located in the gastric glands of the stomach
- Pumps H+ into the lumen of the stomach
- Combines with Cl- to form HCl, allowing for breakdown of proteins
- Also pumps K+ into the mucosa
- Since both ions move against the concentration gradient, ATP is required
- The pump can over-pump and lead to too much stomach acid, resulting in ulcers. Antacids lower H+ and other drugs slow the pump
What is the proton pump?
- Another electrogenic pump that actively transports hydrogen ions (protons)
- Major role in membranes of mitochondria and chloroplasts
Describe co-transport
It is a process in which two substances are simultaneously transported across a membrane by one protein:
- Na+ can renter the cell, but only when it is coupled by glucose
- The sodium-potassium pump works with glucose by providing Na+ for it
Describe symport and antiport
Symport: the movement of 2 substances together in the same direction (ex., Na+ and glucose)
Antiport: the movement of 2 substances together in the opposite direction (ex., Na+/K+ pump)
Explain the endosymbiotic origin theory of the mitochondria
The theory says that early eukaryotic cells engulfed aerobic bacteria, but due to their plasma membrane, they were not digested. The bacteria then continued to perform aerobic respiration, providing excess ATP to the cell and reproducing independently within the cell.
What evidence supports the endosymbiotic origin theory?
Mitochondria and chloroplasts have features that differ from other organelles, relating them to bacteria:
- They are double-membraned
- The chemistry of their inner membrane resembles eubacteria plasma membranes
- They have their own DNA with remnants of eubacterial chromosomes and coding sequences for proteins and RNA which resemble bacterial genes
- They replicate their own DNA and undergo division independently of their host cell
State the components of the phospholipid bilayer and the reaction that produces it
Glycerol bonded to phosphate head (hydrophilic) with two fatty acid tails (hydrophobic)
It is produced via a condensation reaction
Give an example of an organelle that has a catabolic function or an anabolic function
Anabolic: ribosomes
Catabolic: mitochondria
What substances can be metabolised by the body if necessary?
Carbohydrates are the first nutrients most organisms catabolise for energy, but, when necessary, most organisms can also metabolism proteins, lipids, and even nucleic acids.
Explain protein catabolism
- Digested into amino acids
- Amino groups are removed via deamination, converting the groups in NH3 (a useful by-product in plants but waste in animals)
- The remaining portion of the amino acids are converted into components or glycolysis of the Krebs cycle, depending on its type
Explain lipid catabolism
- Digested into glycerol and fatty acids
- Glycerol may be converted into glucose via gluconeogenesis, or it may change into DHAP then PGAL for glycolysis
- Fatty acids are transported to the matrix of the mitochondria where they undergo β-oxidation, where they are cleaved, removing acetyl groups
- These groups combine with coenzyme A to form acetyl-CoA for Krebs
- Each cleave uses 1 ATP but produces one NADH and one FADH2, yielding more energy than glucose
What prompts anaerobic respiration?
When no oxygen is present, Krebs cycle (doesn’t directly rely on oxygen but if no oxygen is present, pyruvate cannot partake in the Krebs cycle) and ETS cannot progress. As a result, pyruvic acid can build up to toxic levels and NAD+ cannot be depleted.
To solve these problems, pyruvic acid is converted in a safer molecule and cells regenerate NAD+ for use in glycolysis again. There are two ways this is done:
Anaerobic Respiration
Describe lactic acid fermentation
This occurs in animals and some bacteria.
- Pyruvate –> lactic acid via accepting H+ and electrons from NADH, freeing up NAD+ allowing for the repetition of glycolysis.
During vigorous exercise, muscle cells use up oxygen faster than it can be supplied, resulting in lots of lactic acid production, causing cramps. Slowing down will allow aerobic respiration to resume, and the useless lactic acid is then transported to the liver where it is converted back to pyruvate.
Anaerobic Respiration
Describe alcoholic fermentation
This occurs in yeast.
- Pyruvate releases CO2 –> acetaldehyde –> ethanol via accepting H+ and electrons from NADH, freeing up NAD+ allowing for the repetition of glycolysis.
Used in the alcohol industry.
What is the purpose of fermentation?
Replenish NAD+
What is the force generated by an electrochemical gradient called?
Proton motive force
