Biology Essentials: Cells, Respiration, Anatomy

Cellular Respiration Stages

Glycolysis: Sugar Breakdown

Breaks down a 6-carbon sugar into two 3-carbon groups.

Krebs Cycle Location and Output

Occurs in the inner membrane of the mitochondria.

Forms 2 ATP.

ETC and ATP Synthase Function

Finishes the breakdown of pyruvic acid molecules to CO₂.

Forms 34 ATP.

ATP and ADP Explained

ATP (Adenosine Triphosphate) becomes ADP (Adenosine Diphosphate) when one phosphate is given away, leaving only two.

ADP becomes ATP when one phosphate is added to complete the three phosphates.

Electron Transport Chain Role

A sequence of electron carrier molecules that transfers electrons and releases energy during cellular respiration.

Fermentation: ATP Without Oxygen

When cells exercise and there is not enough O₂, they use fermentation (ATP without O₂).

Cellular respiration continues but is not the main source of ATP in this situation.

Yeast Fermentation Process

In an anaerobic environment, yeast cells ferment sugar and other foods.

Produces alcohol as a waste product and releases CO₂.

CO₂ creates bubbles and pockets that make bread rise.

Alcohol evaporates during baking.

Cell Biology Basics

Animal vs Plant Cell Differences

Both have a membrane and nucleus.

Plant cells also have a cell wall and chloroplasts (for photosynthesis).

Key Cell Organelles

Nucleus: Cell's Control Center

Stores genetic material in the form of DNA.

Tells the cell what to do (only in eukaryotic cells).

Plasma Membrane Function

Thin outer covering.

Creates the boundary of the cell.

Regulates the flow of chemicals between the cell and its surroundings.

Chloroplasts and Photosynthesis

Only in plant and algae cells.

Where photosynthesis takes place (often called "power sacks").

DNA: Genetic Information

Passes genes and the information it contains from one generation to another.

Base pairing rules:

• Adenine pairs with Thymine (A-T)
• Cytosine pairs with Guanine (C-G)

Energy Flow in Ecosystems

Sun provides light.

Producers do photosynthesis, getting nutrients and O₂.

Consumer eats producer.

Consumer eats consumer.

Cellular respiration equation: Glucose + O₂ = ATP + CO₂ + Water

Using a Microscope Correctly

Steps:

1. Hold by the arm and base.
2. Take the cover off and plug into an outlet.
3. Prepare material on a slide and cover it to prevent movement.
4. Carefully place the slide on the microscope stage.
5. Use wheels to move the stage and improve the view (magnification changes).

Microscope Movement Tips

The letter 'E' appears upside down.

Movements are opposite to the ones you make (e.g., moving the slide right makes the image move left).

Major Human Muscle Groups

• Biceps Brachii: Originates on the scapula, inserts on the ulna. Flexes the elbow and supinates the forearm.
• Triceps Brachii: Originates on the scapula and humerus, inserts on the ulna. Extends the arm.
• Gluteus Maximus: Originates on the gluteal line of the ilium, inserts on the femur. Extends and laterally rotates the hip.
• Abdominals: Originates on the pubic crest, inserts on the sternum and ribs. Flexes the body (trunk).
• Quadriceps Femoris: Includes Rectus Femoris and others, inserts on the tibial tuberosity. Primarily responsible for knee extension, Rectus Femoris also flexes the hip.

Properties of Water

Electrons are not equally shared between atoms, making water polar.

Water molecules form hydrogen bonds.

Cohesion and Adhesion Explained

Cohesion: Molecules of the same kind stick together (e.g., water molecules sticking to other water molecules).

Adhesion: Attraction between different types of molecules (e.g., water molecules sticking to cellulose).

Water Movement in Plants

Cohesion allows water molecules to stick together, forming a continuous stream extending from leaves to roots.

Adhesion allows water molecules to adhere to the cellulose molecules in the walls of the xylem.

As water molecules are removed by transpiration in the leaf, the next molecule moves upwards to take its place, pulling the stream continuously along.

Basic Atomic Structure

Example: Carbon atom

• 6 protons
• 6 neutrons
• 4 valence electrons

Understanding Organic Molecules

Any molecule that contains carbon.