Unit 2 Study Guide: Cell Structure, Metabolism, and Genetics

Cell and Tissue Types

Epithelium Types

Epithelium is a tissue that lines the surfaces and cavities of organs. It is classified based on cell shape:

• Squamous Epithelium: Flat, scale-like cells; found in areas of diffusion (e.g., alveoli).

• Cuboidal Epithelium: Cube-shaped cells; often found in glands and kidney tubules.

• Columnar Epithelium: Tall, column-like cells; found in digestive tract lining.

Muscle Tissue Types

• Skeletal Muscle: Voluntary, striated, attached to bones; responsible for movement.

• Smooth Muscle: Involuntary, non-striated; found in walls of internal organs.

• Cardiac Muscle: Involuntary, striated; found only in the heart, with intercalated discs.

Producers and Consumers

• Producers: Organisms (e.g., plants) that synthesize their own food via photosynthesis.

• Consumers: Organisms that obtain energy by eating other organisms.

Autotrophs vs. Heterotrophs

• Autotrophs: Produce their own food from inorganic sources (e.g., plants).

• Heterotrophs: Obtain food by consuming other organisms (e.g., animals).

Nutrition Concepts

• Under-nourishment: Insufficient caloric intake.

• Malnourishment: Lack of essential nutrients despite adequate calories.

• Simple Carbohydrates: Monosaccharides and disaccharides; quick energy source.

• Complex Carbohydrates: Polysaccharides; slower energy release.

• LDL Cholesterol: 'Bad' cholesterol; can lead to plaque buildup in arteries.

• HDL Cholesterol: 'Good' cholesterol; helps remove LDL from bloodstream.

Vitamin Supplements, Organic, and Non-GMO Foods

• Vitamin Supplements: Can prevent deficiencies but may cause toxicity if overused.

• Organic Foods: Grown without synthetic pesticides; may reduce exposure to chemicals.

• Non-GMO Foods: Not genetically modified; consumer preference for natural products.

Microscopy and Organ Systems

Microscope Slide Recognition

Ability to identify tissue types under a microscope is essential for understanding structure-function relationships.

Main Organ Systems and Functions

• Digestive System: Breaks down food and absorbs nutrients.

• Circulatory System: Transports blood, nutrients, and gases.

• Respiratory System: Facilitates gas exchange.

• Nervous System: Coordinates body activities via electrical signals.

• Muscular System: Enables movement.

• Endocrine System: Regulates processes via hormones.

• Immune System: Defends against pathogens.

• Excretory System: Removes waste products.

• Reproductive System: Produces offspring.

Biochemistry and Metabolism

Key Terms

• Entropy: Measure of disorder in a system.

• Activation Energy: Minimum energy required to start a reaction.

• Enzyme Active Site: Region where substrate binds and reaction occurs.

• Substrate: Molecule upon which an enzyme acts.

• Inhibitor: Substance that decreases enzyme activity.

• Chemiosmosis: Movement of ions across a membrane to generate ATP.

• Asexual Reproduction: Offspring from a single parent; genetically identical.

• Sexual Reproduction: Offspring from two parents; genetic variation.

• Homologous Chromosomes: Chromosome pairs with same genes but possibly different alleles.

Comparisons

• Exergonic vs. Endergonic Reactions: Exergonic releases energy; endergonic requires energy.

• Phosphorylation vs. Substrate-level Phosphorylation: Phosphorylation adds phosphate; substrate-level occurs directly in metabolic reactions.

• Cofactors vs. Coenzymes: Cofactors are inorganic; coenzymes are organic molecules aiding enzymes.

• Competitive vs. Non-competitive Inhibition: Competitive binds active site; non-competitive binds elsewhere.

• Aerobic vs. Anaerobic Respiration: Aerobic uses oxygen; anaerobic does not.

• Mitosis vs. Meiosis: Mitosis produces identical cells; meiosis produces gametes with genetic variation.

• Cytokinesis in Plants vs. Animals: Plants form cell plate; animals form cleavage furrow.

Enzyme Activity Factors

• pH: Extreme pH can denature enzymes.

• Temperature: High temperature can denature; low slows activity.

• Heavy Metals: Can inhibit enzyme function by binding to active sites.

Redox Reactions and ATP Generation

Redox reactions transfer electrons, powering the electron transport chain and ATP synthesis.

• NADH: Electron carrier; donates electrons to the chain.

• ATP: Main energy currency of the cell.

Equation for ATP synthesis:

$\text{ADP} + \text{P}_i \rightarrow \text{ATP}$

Poisons Affecting Cellular Respiration

• Block electron transport chain.

• Inhibit ATP synthase.

• Disrupt membrane integrity.

Cell Division Factors

• Growth signals.

• DNA integrity.

• Availability of nutrients.

Chromosome Alterations

• Deletion

• Duplication

• Inversion

• Translocation

Cellular Respiration and Metabolic Pathways

Glycolysis, Citric Acid Cycle, Oxidative Phosphorylation

These pathways break down glucose to generate ATP.

• Glycolysis: Occurs in cytoplasm; produces pyruvate, ATP, NADH.

• Citric Acid Cycle: Occurs in mitochondria; produces CO2, ATP, NADH, FADH2.

• Oxidative Phosphorylation: Electron transport chain and chemiosmosis; produces most ATP.

ATP Yield Table

Pathway	Main Products
Glycolysis	2 ATP, 2 NADH, 2 Pyruvate
Citric Acid Cycle	2 ATP, 6 NADH, 2 FADH2, 4 CO2
Oxidative Phosphorylation	~34 ATP, H2O

Cell Division and Genetics

Phases of Mitosis and Meiosis

• Mitosis: Prophase, Metaphase, Anaphase, Telophase

• Meiosis: Meiosis I (Prophase I, Metaphase I, Anaphase I, Telophase I), Meiosis II (Prophase II, Metaphase II, Anaphase II, Telophase II)

Cancer and Cell Cycle

Cancer results from uncontrolled cell division due to mutations in cell cycle regulatory genes.

Genetic Variability in Meiosis

• Crossing over during Prophase I

• Independent assortment

• Random fertilization

Sex Determination

• Chromosomal level: XX (female), XY (male) in humans

Enzyme Kinetics Lab

Results Discussion

• Enzyme activity depends on substrate concentration, pH, and temperature.

• Graphical analysis shows optimal conditions for activity.

Michaelis-Menten Equation:

$v = \frac{V_{max} [S]}{K_m + [S]}$

Example: Measuring reaction rate at different substrate concentrations to determine enzyme efficiency.

Additional info: Academic context was added to expand brief points and ensure completeness.