Biology Chapter 7: Cell Structure Overview

Cell Theory and Basics

• All living things are composed of cells, which are the fundamental units of structure and function.
• New cells arise from existing cells, forming the basis of cell theory, a core biological principle.

Prokaryotes vs. Eukaryotes

• Prokaryotic cells: Lack a nucleus, have genetic material distributed throughout the cell.
• Eukaryotic cells: Contain a nucleus that encapsulates genetic material (DNA).

Cell Structures

• A cell is defined as the basic unit of life.
• The nucleus is a larger membrane-bound organelle housing the cell's DNA.
• Organelle refers to "little organs," specialized structures within the cell, such as mitochondria and chloroplasts.

Nucleus and Genetic Material

• The nuclear envelope consists of two membranes surrounding the nucleus, serving as a barrier.
• Chromatin is granular material within the nucleus, primarily made of tightly coiled DNA and proteins.
• The nucleolus, located within the nucleus, is responsible for ribosome assembly.

Protein Synthesis

• Ribosomes are small particles where protein assembly occurs; they are composed of RNA and proteins.
• The endoplasmic reticulum is an internal membrane system where lipid components and protein modifications occur.
• The Golgi apparatus modifies, sorts, and packages proteins for transport.

Cellular Metabolism

• Mitochondria convert chemical energy from food into usable compounds for the cell.
• Chloroplasts, present in plant cells, capture sunlight to produce chemical energy through photosynthesis.

Cell Support Structures

• The cytoskeleton is a network of protein filaments that provides structural support and facilitates cell movement.
• Centrioles, located near the nucleus in animal cells, play a role in cell division.

Cell Membranes

• The cell membrane is a flexible barrier controlling the passage of substances in and out of the cell, providing protection and support.
• The cell wall, found in plants, fungi, and some bacteria, offers additional support and protection around the cell membrane.

Molecular Transport Mechanisms

• Diffusion is the movement of molecules from areas of higher concentration to lower concentration, occurring without energy expenditure.
• Osmosis specifically refers to the diffusion of water through a selectively permeable membrane.
• Facilitated diffusion employs protein channels for specific molecule transport across membranes.

Concentration and Equilibrium

• Concentration measures the mass of solute in a given solution volume.
• Equilibrium occurs when solute concentrations are equal throughout a system.

Solution Conditions

• Isotonic solutions have equal concentrations on both sides.
• Hypertonic solutions have higher solute concentrations outside the cell, leading to potential cell shrinkage.
• Hypotonic solutions have lower solute concentrations outside the cell, which may cause the cell to swell.

Active Transport and Vesicular Transport

• Active transport requires energy to move materials against concentration gradients.
• Endocytosis involves cell membrane pockets engulfing materials; phagocytosis refers to "cell eating," while pinocytosis involves liquid uptake.
• Exocytosis allows cells to release large amounts of material into the exterior.

Cell Specialization and Organization

• Cell specialization permits diverse cell types to develop and perform specific tasks.
• The organization levels in multicellular organisms are: cells, tissues, organs, and organ systems.
• Tissues consist of similar cells performing particular functions, while organs are collections of tissues working in tandem. Organ systems are groups of organs collaborating to fulfill specific biological roles.

Explore the fundamental concepts of cell structure and function with flashcards from Chapter 7. This quiz covers key topics like the cell theory and the characteristics of prokaryotic and eukaryotic cells. Test your knowledge and enhance your understanding of cellular biology.