Biology Chapter 1: Structures vs Functions

Biology Chapter 1: Structures vs Functions

• This chapter covers the relationship between the structure and function of biological entities, specifically looking at cells.
• Key concepts include cells, cell theory, prokaryotic cells, eukaryotic cells, and the organization of life.

Cell Theory

• All living things are composed of cells.
• Cells are the smallest working units of living things.
• All cells come from pre-existing cells via cell division.

Definition of a Cell

• A cell is the smallest unit capable of carrying out life functions.

Types of Cells: Prokaryotic

• Lack internal membrane-bound structures (organelles).
• Have few internal structures.
• Found in single-celled organisms like bacteria.
• Examples: Bacteria, blue-green algae
• Features such as cell wall, ribosomes, flagella, nucleoid (DNA)

Types of Cells: Eukaryotic

• Contain organelles surrounded by membranes.
• Found in complex organisms such as plants, animals, fungi, and protists.
• Include plant cells and animal cells.

Cells in Humans

• Smallest cell: Sperm cell, size ~5 μm
• Largest cell: Ovum cell, size ~120 μm
• Longest cell: Nerve cell, size ~1 m

Cell Structure

• Compound microscope: Magnification of 2000X, used to study basic cell structures
• Electron microscope: Magnification of 500,000X, used to study the ultrastructure (detailed internal structure) of cells.

Plant Cells

• Contain chloroplasts for photosynthesis.
• Generally larger than animal cells.
• Have cell walls (composed of cellulose).
• Larger vacuoles than animal cells.
• Lack centrioles.

Animal Cells

• Generally smaller than plant cells.
• Lack cell walls.
• Contain centrioles.
• Smaller vacuoles.
• Have specialized structures like mitochondria, Golgi bodies and lysosomes.

Cell Organelles and their Roles

• Nucleus: Directs cellular activities. Contains DNA.
• Cell membrane: Controls movement of substances into and out of the cell; separates the cell's contents from the outside environment. Has a double layer.
• Ribosomes: Build proteins from amino acids.
• Golgi body: Modifies, sorts and packages materials synthesized within the cell. It delivers synthesized materials both inside and outside the cell.
• Mitochondria: Produces ATP (energy) through chemical reactions. Found in plant cells as well.
• Chloroplast: Found in plant cells. Produces energy through photosynthesis; uses sunlight to convert carbon dioxide and water into sugar.
• Vacuoles: Storage containers. Large in plant cells.
• Lysosomes: Contain enzymes that break down waste products. Found in animal cells.
• Endoplasmic reticulum (ER): Support to the cytoplasm; produces proteins and lipids. Rough ER has ribosomes attached. Smooth ER synthesizes lipids. Also involved in drug detoxification in liver cells.
• Cytoplasm: Gel-like substance filling the cell. Contains hereditary materials (DNA).
• Chromosomes: Contain DNA, the instructions for traits and characteristics; found in the nucleus
• Nucleolus: Inside the nucleus; makes ribosomes

Levels of Organization in Living Organisms

• Cell: Basic unit
• Tissues: Similar cells working together.
• Organs: Tissues working together.
• Organ systems: Organs working together.
• Organism: All systems working together.

Cilia and Flagella (both used for movement)

• Cilia: Numerous small hair-like projections.
• Flagella: Larger whip-like appendage(s).

Shape of Human Cells

• Varies depending on the function of the cell.

Bacteria Cell

• Components: Capsule, cell wall, plasma membrane, cytoplasm, flagella, food granule, plasmid(DNA), ribosomes, nucleoid, pili

Explore the key concepts of Biology Chapter 1, focusing on the relationship between the structure and function of cells. Understand the differences between prokaryotic and eukaryotic cells, and learn about the cell theory and its significance in biology.