Chapter 8 Cell Biology Study Guide

Flashcards testing concepts from Chapter 8, covering cell theory, microscopes, cell structures, organelles, cell transport mechanisms, homeostasis, and cellular organization.

What are the three main points of the cell theory?

Cells are the basic units of structure and function in living things, new cells are produced from existing cells, and all living things are made up of cells.

Why are stains and dyes used when observing cells under a light microscope?

Cells are nearly transparent, so stains and dyes are used to make cell structures visible under a light microscope.

What are the characteristics and image properties of a transmission electron microscope?

It makes it possible to explore cell structures and large protein molecules, produces flat 2D images, and requires specimens to be cut extremely thin so the electron beam can pass through.

How does a scanning electron microscope work and what type of image does it produce?

A pencil-like beam scans the surface of the specimen, producing 3D images.

What are the key characteristics and examples of prokaryotes?

Prokaryotes do not contain a nucleus, have DNA in the cytoplasm, are simpler, smaller, and unicellular. Examples include bacteria, protists, and algae.

What are the key characteristics and examples of eukaryotes?

Eukaryotes contain a nucleus with DNA inside, are larger, more complex, and can be multicellular or unicellular. Examples include animals, fungi, and plants.

What is the primary function of the cell nucleus?

It contains nearly all the cell's DNA and with it the coded instructions for making proteins and other important molecules.

What process begins inside the nucleolus?

The assembly of ribosomes begins in the nucleolus.

What is the function of ribosomes?

Ribosomes produce proteins.

What are the primary differences between the Rough ER and Smooth ER?

Rough ER has ribosomes on its surface, while Smooth ER lacks ribosomes and produces carbohydrates.

What is the function of the Golgi apparatus?

It modifies, sorts, and packages proteins and other materials for storage or release.

What are the functions of vacuoles and lysosomes?

Vacuoles store materials, while lysosomes break down materials as the cleanup crew of the cell.

Which cellular structures are found ONLY in plant cells and not animal cells?

Cell walls and chloroplasts.

How is the lipid bilayer of the cell membrane structured?

Hydrophilic (water-loving) heads are exposed to the outside of the cell and cytoplasm, while hydrophobic (water-fearing) tails form an oily layer inside the membrane that keeps water out.

What are the two principal protein filaments of the cytoskeleton and their functions?

Microfilaments are threadlike structures that form a tough, flexible framework supporting the cell and aiding movement; microtubules are hollow structures that maintain cell shape and assist in cell division.

What is homeostasis?

The state of relatively constant internal physical and chemical conditions.

How do passive transport and active transport differ?

Passive transport uses no energy, moves smaller molecules, and flows with the concentration gradient (high to low). Active transport uses cellular energy, moves larger molecules, and flows against the concentration gradient (low to high).

What state is reached when particle concentrations are equal on both sides of a cell membrane?

Equilibrium, where molecules continue to move across the membrane in both directions.

What is facilitated diffusion?

The process where molecules that cannot directly diffuse across the membrane pass through special protein channels, such as red blood cells using protein carriers for glucose.

What is osmosis and what channel proteins facilitate it?

Osmosis is the diffusion of water through a selectively permeable membrane from higher to lower concentration, facilitated by water channel proteins called aquaporins.

What do the terms isotonic, hypertonic, and hypotonic mean?

Isotonic means 'same strength' (equal concentration), hypertonic means 'above strength' (higher solute concentration), and hypotonic means 'below strength' (lower solute concentration).

What is osmotic pressure?

The net movement of water out of or into the cell.

What are the two types of active transport?

Molecular transport (small molecules/ions pumped by membrane proteins) and bulk transport (larger molecules and solid clumps moved via endocytosis or exocytosis).

What is the difference between endocytosis, phagocytosis, pinocytosis, and exocytosis?

Endocytosis takes material into the cell via pockets (phagocytosis is cell eating; pinocytosis is cell drinking), while exocytosis releases large amounts of material out of the cell.

How do unicellular organisms maintain homeostasis?

They grow, respond to the environment, transform energy, and reproduce.

What is the organizational hierarchy of multicellular organisms?

Cells -> tissue -> organ -> organ system (e.g., Neurons -> nerve tissue -> brain -> nervous system).

How do cells in large organisms communicate with one another?

They communicate by means of chemical signals passed from one cell to another, requiring a receptor on the receiving cell for the signaling molecule to bind.