membrane and respiration Flashcards
What is the major component of the plasma membrane?
A double layer of phospholipids.
Where are the hydrophilic heads and hydrophobic tails of phospholipids located in the membrane?
Hydrophilic heads face the aqueous environment, and hydrophobic tails face inward.
What contributes to the fluidity of the plasma membrane?
The lateral movement of phospholipids.
How do unsaturated hydrocarbon tails affect membrane fluidity?
They cause kinks that prevent tight packing, making the membrane more fluid.
Which molecules pass through the membrane more easily: hydrophilic or hydrophobic molecules?
Hydrophobic molecules pass through the membrane more easily.
What are the two types of membrane proteins?
Peripheral proteins (bound to the surface) and transmembrane (integral) proteins (span the entire membrane).
How does cholesterol affect membrane fluidity?
It increases fluidity and prevents solidification at cold temperatures.
Name the six major functions of membrane proteins.
Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and ECM.
how do membrane carbohydrates assist in cell recognition?
They bind to molecules on the extracellular side of the membrane, helping cells identify each other.
What is the difference between channel proteins and carrier proteins?
Channel proteins provide a tunnel for molecules to pass, while carrier proteins bind to molecules and change shape to move them across the membrane.
What is the function of the sodium-potassium pump?
It moves sodium ions (Na+) out of the cell and potassium ions (K+) into the cell, maintaining concentration gradients.
What is the purpose of active transport?
It moves substances against their concentration gradient, requiring energy (ATP).
What is a gated ion channel?
An ion channel that opens or closes in response to a stimulus, regulating ion flow.
What are the steps in active transport for the sodium-potassium pump?
1.Na+ binds to the pump.
2.ATP phosphorylation changes the pump’s shape.
3.Na+ is released outside.
4.K+ binds, and phosphate is released.
5. K+ is released, and the pump returns to its original shape.
What is the difference between symport, antiport, and uniporter?
Uniporter transports one molecule in its concentration gradient.
Symport moves multiple molecules in the same direction.
Antiport moves multiple molecules in opposite directions.
What initiates signal transduction?
Signal transduction begins when a ligand binds to a receptor, triggering a cascade of cellular or systemic responses.
What is the first law of thermodynamics?
Energy cannot be created or destroyed; it can only be transformed from one form to another (e.g., electrical energy from falling water).
What is the difference between exocytosis and endocytosis?
Exocytosis: Vesicles fuse with the membrane to release contents outside the cell.
Endocytosis: The cell engulfs materials by forming vesicles from the membrane.
How does HIV infect cells?
HIV binds to CD4 receptors and CCR5 co-receptors on T-helper cells, allowing infection. Individuals lacking CCR5 are resistant to HIV.
Name the three types of endocytosis.
Phagocytosis (“cellular eating”)
Pinocytosis (“cellular drinking”)
Receptor-mediated endocytosis
What does the second law of thermodynamics state?
In every energy transaction, useful energy decreases, and some energy escapes as heat.
What’s the difference between autotrophs and heterotrophs?
Autotrophs make their own food (e.g., plants via photosynthesis), while heterotrophs consume other organisms for energy (e.g., humans).
What does ATP hydrolysis do?
ATP hydrolysis breaks the phosphoanhydride bond, releasing 7 kcal/mol of energy.
What are redox reactions in cellular respiration?
Oxidation is the loss of electrons (glucose to CO2) and reduction is the acceptance of electrons (O2 to H2O).
What are the 3 main stages of cellular respiration?
- Glycolysis: Breaks glucose into 2 pyruvates, producing 2 ATP and 2 NADH.
- Citric Acid Cycle: Breaks down pyruvate to CO2, yielding 2 ATP, 6 NADH, and 2 FADH2.
- ETC & Oxidative Phosphorylation: Produces most ATP, 28 ATP from NADH and FADH2 oxidation.
What is the net result of glycolysis?
Glycolysis splits glucose into 2 pyruvates, producing a net of 2 ATP and 2 NADH.
What are the two types of ATP formation in cellular respiration?
Substrate-Level Phosphorylation (SLP): Direct ATP transfer. Oxidative Phosphorylation (OP): ATP formed through ETC and chemiosmosis.
What is produced per turn of the citric acid cycle?
1 ATP, 3 NADH, 1 FADH2, and 2 CO2. After two turns (per glucose), it produces 4 CO2, 2 ATP, 6 NADH, and 2 FADH2.
How do cyanide and carbon monoxide disrupt cellular respiration?
They bind to cytochrome oxidase in the ETC, blocking electron flow to oxygen and halting ATP production.
How does brown adipose tissue help in newborns and hibernating animals?
It generates heat instead of ATP by bypassing ATP synthase through a proton pathway.
What is chemiosmosis?
The movement of H+ ions across a membrane, driving ATP synthesis via ATP synthase.
How does the electron transport chain produce ATP?
Electrons move down the chain, creating a proton gradient that powers ATP synthesis via ATP synthase. This produces 28 ATP.
What happens during alcoholic fermentation?
Pyruvate is converted to ethanol, releasing CO2 in the process. Used in brewing, winemaking, and baking.
What is lactic acid fermentation?
A process where pyruvate is converted into lactic acid, helping regenerate NAD+ during anaerobic conditions, such as in muscles or yogurt production.
How much ATP does fermentation produce compared to cellular respiration?
Fermentation produces only 2 ATP, whereas aerobic respiration can produce up to 32 ATP.
Why is glycolysis considered an ancient process?
It is believed to have existed in early prokaryotes before oxygen was available in the atmosphere, making it a key process for life over 2.7 billion years ago.
What foods are made using fermentation by microorganisms?
Cheese, sour cream, yogurt, pickles, olives, and some meats like sausage.
How does yogurt differ from cheese in production?
yogurt is made by fermenting milk with bacteria, while cheese is made by coagulating milk with enzymes or acids and then processing the curds.
What are probiotics and how do they benefit health?
Probiotics are beneficial bacteria and yeast that support gut health, aid digestion, boost the immune system, and help treat conditions like diarrhea and eczema.
