Chapters 1 - 3 Study Guide

What does homeostasis refer to?

The body's ability to maintain a stable internal environment despite changes in external conditions.

What is the basic unit of life?

Cell.

List the levels of organization of living organisms from smallest to largest.

Atom, Molecule, Organelle, Cell, Tissue, Organ, Organ System, Organism.

What role do mitochondria play in the cell?

Site of ATP production through cellular respiration.

What is negative feedback in the context of homeostasis?

A response that reduces the stimulus to stabilize the system.

Example of positive feedback in the body?

Childbirth: uterine contractions lead to more contractions until delivery.

What is the function of ribosomes?

Protein synthesis.

What are lysosomes responsible for?

Digestion and waste removal.

What happens during glycolysis?

ATP is produced in the cytoplasm; 2 ATP are created.

What is the primary site of ATP production in the cell?

Mitochondria.

How many ATP are produced in the Electron Transport Chain (ETC)?

Approximately 34 ATP.

What characterizes integral proteins in the cell membrane?

They span the membrane and transport molecules.

Define facilitated diffusion.

Movement of molecules through a membrane protein from high to low concentration.

What does cholesterol do in the cell membrane?

Stabilizes membrane fluidity.

Describe osmosis.

Movement of water across a semipermeable membrane.

What type of transport uses ATP to move molecules against their gradient?

Primary Active Transport.

What is osmolarity?

The concentration of solute particles in solution.

What occurs in a hypertonic solution?

Water exits the cell due to higher solute concentration outside.

What is the purpose of the Golgi apparatus?

Modifies, sorts, and packages proteins for transport.

What is the difference between penetrating and non-penetrating solutes?

Penetrating solutes can cross the membrane, while non-penetrating solutes cannot.

Describe Fick’s Law of Diffusion.

Rate of diffusion = (Concentration gradient × Surface area × Permeability) / Distance.

What is the function of the cytoskeleton?

Provides structure, shape, and aids in cell movement.

What is the role of the plasma membrane?

Controls movement of substances in and out of the cell.

What happens in a hypotonic solution?

Water enters the cell due to lower solute concentration outside.

What do peroxisomes do?

Detoxification and breakdown of fatty acids.

How is ATP generated in the ETC?

Electrons create a proton gradient that drives ATP synthase.

What type of cells have a high mitochondria count?

Cells with a high energy demand, such as muscle cells and neurons.

What is the function of smooth endoplasmic reticulum?

Synthesizes lipids and detoxifies drugs.

How does active transport differ from passive transport?

Active transport requires energy, while passive transport does not.

What is the function of carbohydrates in the cell membrane?

Involved in cell recognition as glycoproteins and glycolipids.

What defines isotonic solutions?

Equal solute concentration inside and outside the cell.

What is the main function of the nucleus?

Contains genetic material (DNA) and controls cell activities.

What is the significance of high ribosome counts in certain cells?

Indicates cells that produce a lot of protein, such as pancreas cells producing insulin.

What is tissue?

Groups of similar cells performing a common function.

What is the definition of an organism?

A complete living entity capable of independent existence.

Give an example of a control mechanism involved in homeostasis.

Regulation of blood sugar by insulin.