Biology Chapter: Essential Nutrients and Transport

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Questions and Answers

What happens to a cell in a hypertonic solution?

The cell maintains its size and shape.

The cell bursts due to excess water.

The cell shrinks as water moves out. (correct)

The cell takes in water and swells.

Which phase of bacterial growth is characterized by rapid cell division?

Log (Exponential) Phase (correct)

Stationary Phase

Death Phase

Lag Phase

What is the primary function of enzymes in biological reactions?

To act as waste products in the reaction.

To serve as substrates for reactions.

To speed up reactions by lowering activation energy. (correct)

To increase the activation energy required.

What process breaks down large molecules into smaller ones, releasing energy?

Catabolism Signup and view all the answers

Which of the following describes competitive inhibition in enzyme activity?

An inhibitor competes with the substrate for the active site. Signup and view all the answers

What is the final product of aerobic respiration?

Carbon dioxide and water Signup and view all the answers

What is the primary end product of lactic acid fermentation?

Lactic acid Signup and view all the answers

What is the function of ATP in cellular processes?

To provide energy for cellular work. Signup and view all the answers

How many ATP molecules are produced during fermentation?

2 ATP Signup and view all the answers

What is the function of NAD⁺ during glycolysis?

To accept electrons and regenerate NAD⁺ Signup and view all the answers

Which of the following is true about anaerobic respiration?

It produces less ATP than aerobic respiration. Signup and view all the answers

What is herd immunity?

Protection for non-immune individuals due to high immunity in the population Signup and view all the answers

What type of reactions are oxidation-reduction (redox) reactions?

Reactions where electrons are transferred Signup and view all the answers

What is an example of a non-competitive enzyme inhibitor?

A molecule altering enzyme shape without blocking the active site Signup and view all the answers

What occurs during the Krebs Cycle?

Reduction of NAD⁺ to NADH Signup and view all the answers

How does anaerobic respiration primarily differ from aerobic respiration?

Anaerobic respiration produces less ATP compared to aerobic respiration Signup and view all the answers

Which category of nutrients includes carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur?

Macronutrients Signup and view all the answers

What do autotrophs use to make their own food?

Inorganic compounds and energy from sunlight or chemicals Signup and view all the answers

Which type of transport requires energy to move substances against their concentration gradient?

Active transport Signup and view all the answers

What term describes the movement of water across a selectively permeable membrane?

Osmosis Signup and view all the answers

What occurs during hypotonic conditions in a cell?

Water moves in, potentially causing the cell to swell and burst Signup and view all the answers

Which type of cell transport involves carrier proteins to assist in molecule movement?

Facilitated diffusion Signup and view all the answers

What is a characteristic of heterotrophic organisms?

They obtain energy by consuming other organisms. Signup and view all the answers

Which of the following processes is known as 'cell drinking'?

Pinocytosis Signup and view all the answers

Study Notes

Essential Nutrients for Cells

Essential Nutrient: A nutrient required for survival that a cell cannot synthesize on its own.
Macronutrients: Required in large quantities for cell structure and metabolism; examples include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS).
Micronutrients: Needed in smaller amounts; often for enzyme function and protein structure; examples include zinc, iron, and manganese.

Autotrophs vs. Heterotrophs

Autotrophs: Organisms that can make their own food using inorganic compounds (like CO₂) and energy from sunlight or chemicals (e.g., plants, algae).
Heterotrophs: Organisms that obtain energy by consuming other organisms (e.g., animals, fungi).

Types of Transport in Cells

Simple Diffusion: Movement of molecules from an area of high concentration to low concentration without energy or assistance; examples: oxygen and carbon dioxide moving across membranes.
Facilitated Diffusion: Similar to simple diffusion, but uses carrier proteins or channel proteins to help large or charged molecules cross the membrane without energy; example: Glucose transport into cells.
Active Transport: Requires energy (usually ATP) to move molecules against the concentration gradient (from low to high concentration); example: The sodium-potassium pump (Na⁺/K⁺ pump), which pumps sodium out of the cell and potassium into the cell.
Endocytosis: The process by which a cell engulfs material from its external environment by surrounding it with a section of its membrane, which then pinches off to form a vesicle inside the cell.
- Phagocytosis: “Cell eating” for solid particles (e.g., immune cells engulfing bacteria).
- Pinocytosis: “Cell drinking” for liquids.

Osmosis and Tonicity

Osmosis: The diffusion of water across a selectively permeable membrane from an area of lower solute concentration to higher solute concentration.
Tonicity: The effect of solute concentration on cell shape and water movement.
- Isotonic: Solute concentration is equal inside and outside the cell; water moves in and out equally.
- Hypotonic: Lower solute concentration outside the cell; water moves into the cell, possibly causing it to swell and burst (lysis).
- Hypertonic: Higher solute concentration outside the cell; water moves out of the cell, causing it to shrink (crenation).

Binary Fission and Bacterial Growth

Binary Fission: A form of asexual reproduction in bacteria where one cell divides into two genetically identical cells. Steps include DNA replication, elongation of the cell, and division into two daughter cells.
Bacterial Growth Curve:
- Lag Phase: Bacteria are adjusting to their environment, preparing for growth.
- Log (Exponential) Phase: Bacteria divide rapidly, and population size increases exponentially.
- Stationary Phase: Nutrients start to deplete, and waste products accumulate; growth rate slows.
- Death Phase: Cells die faster than they reproduce due to lack of nutrients and accumulation of toxins.

Metabolism

Metabolism: All of the chemical reactions that occur within a cell to maintain life.
Anabolism: Building large molecules from smaller ones (requires energy).
Catabolism: Breaking down large molecules into smaller ones (releases energy).

Enzymes

Enzymes: Biological catalysts that speed up reactions by lowering the activation energy.
Active Site: The region of the enzyme where the substrate binds.
Substrate: The molecule that the enzyme acts upon.
Product: The result of the enzyme-mediated reaction.
Enzyme Inhibition:
- Competitive Inhibition: A molecule similar to the substrate competes for the active site, blocking the substrate.
- Non-Competitive Inhibition: A molecule binds to a different part of the enzyme (allosteric site), changing its shape and preventing the substrate from binding to the active site.

Energy Production

ATP (Adenosine Triphosphate): The energy currency of the cell, composed of adenine, ribose, and three phosphate groups. When ATP is broken down into ADP (adenosine diphosphate) and a phosphate group, energy is released for cellular work.

Types of Catabolism

Aerobic Respiration: Uses Oxygen as the final electron acceptor in the electron transport chain. Produces a large amount of ATP (36-38 ATP per glucose molecule). Byproducts: Carbon dioxide (CO₂) and water (H₂O). Steps: Glycolysis → Krebs Cycle → Electron Transport Chain (ETC).
Anaerobic Respiration: Does not use oxygen; instead, uses other inorganic molecules (e.g., nitrate, sulfate) as final electron acceptors. Produces less ATP than aerobic respiration (2-36 ATP per glucose molecule). Byproducts vary depending on the electron acceptor.
Fermentation: No oxygen required. Only uses glycolysis, resulting in 2 ATP per glucose molecule. Pyruvate is converted into organic molecules like lactic acid or ethanol to regenerate NAD⁺ for glycolysis to continue. Examples: Lactic acid fermentation (in muscles) and alcohol fermentation (in yeast).

Flu Virus and Immunity

Flu Virus (Influenza): A highly contagious virus that affects the respiratory system. It evolves quickly, which is why flu vaccines need to be updated regularly.
Flu Vaccine: A preventive shot that helps your immune system recognize and fight the flu virus if you’re exposed.
Herd Immunity: When a large portion of the population is immune to a disease (through vaccination or previous illness), it helps protect those who are not immune by reducing the spread of the virus.

Key Vocabulary and Concepts

Oxidation-Reduction (Redox) Reactions: Chemical reactions where electrons are transferred from one molecule to another. Oxidation is the loss of electrons, and reduction is the gain of electrons.
Electron Carriers: Molecules like NAD⁺ and FAD that transport electrons during cellular respiration. They are reduced to NADH and FADH₂ and then donate electrons to the ETC to produce ATP.

Potential Exam Questions

Explain the difference between facilitated diffusion and active transport.
What are the stages of aerobic respiration, and where do they occur?
How do competitive and non-competitive enzyme inhibitors differ?
Why does anaerobic respiration produce less ATP than aerobic respiration?
How do bacterial cells divide, and what are the four phases of bacterial growth?

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Description

Test your understanding of essential nutrients for cells, including macronutrients and micronutrients, as well as the differences between autotrophs and heterotrophs. Delve into types of cellular transport mechanisms such as simple diffusion and facilitated diffusion. This quiz will enhance your knowledge of cellular biology concepts.