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; common in glands and kidney tubules.

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

Example: Squamous epithelium facilitates gas exchange in lungs.

Muscle Tissue Types

Muscle tissue enables movement and is classified as:

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

• Smooth Muscle: Involuntary, non-striated; found in organs like intestines.

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

Example: Cardiac muscle contracts rhythmically to pump blood.

Producers vs. 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 (e.g., plants, algae).

• Heterotrophs: Depend on other organisms for food (e.g., animals).

Nutrition Concepts

• Under-nourishment: Insufficient caloric intake.

• Malnourishment: Lack of essential nutrients despite adequate calories.

Carbohydrates

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

• Complex Carbohydrates: Polysaccharides; slower energy release.

Cholesterol Types

• LDL (Low-Density Lipoprotein): "Bad" cholesterol; can lead to plaque buildup.

• HDL (High-Density Lipoprotein): "Good" cholesterol; helps remove LDL.

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.

Pros and Cons: Supplements can fill dietary gaps but are not always necessary; organic foods may be healthier but are often more expensive.

Microscope Slide Recognition

Recognize tissue types by cell shape and arrangement under the microscope.

Organ Systems Overview

Main organ systems and their functions:

• Digestive System: Breaks down food for nutrient absorption.

• Circulatory System: Transports nutrients and oxygen.

• Nervous System: Coordinates responses to stimuli.

• Respiratory System: Gas exchange.

• Muscular System: Movement.

• Endocrine System: Hormone regulation.

• Immune System: Defense against pathogens.

Metabolism and Enzyme Function

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 acted upon by an enzyme.

• Inhibitor: Substance that decreases enzyme activity.

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

Reproduction Types

• Asexual Reproduction: Offspring from one parent; genetically identical.

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

Homologous Chromosomes

Chromosomes with the same genes but possibly different alleles; one from each parent.

Exergonic vs. Endergonic Reactions

• Exergonic: Release energy; spontaneous.

• Endergonic: Require energy input; non-spontaneous.

Phosphorylation Types

• Phosphorylation: Addition of phosphate group to a molecule.

• Substrate-Level Phosphorylation: Direct transfer of phosphate to ADP.

Cofactors vs. Coenzymes

• Cofactors: Non-protein helpers for enzymes (e.g., metal ions).

• Coenzymes: Organic cofactors (e.g., NAD+, FAD).

Enzyme Inhibition

• Competitive Inhibition: Inhibitor binds to active site, blocking substrate.

• Non-Competitive Inhibition: Inhibitor binds elsewhere, changing enzyme shape.

Aerobic vs. Anaerobic Respiration

• Aerobic: Uses oxygen; produces more ATP.

• Anaerobic: No oxygen; less ATP, produces lactic acid or ethanol.

Mitosis vs. Meiosis

• Mitosis: Produces two identical cells; growth and repair.

• Meiosis: Produces four genetically unique gametes; sexual reproduction.

Cytokinesis in Plants vs. Animals

• Plants: Cell plate forms to divide cells.

• Animals: Cleavage furrow pinches cell in two.

Enzyme Activity Factors

• pH: Extreme pH can denature enzymes.

• Temperature: High temperatures denature; low temperatures slow activity.

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

Redox Reactions and ATP Generation

Redox reactions transfer electrons; NADH carries electrons to electron transport chain, generating ATP via chemiosmosis.

Equation:

$\text{NADH} + \text{H}^+ + \frac{1}{2} \text{O}_2 \rightarrow \text{NAD}^+ + \text{H}_2\text{O}$

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

Poisons Affecting Cellular Respiration

• Block electron transport chain (e.g., cyanide).

• Inhibit ATP synthase.

• Disrupt membrane integrity.

Factors in Cell Division

• Cell size

• DNA integrity

• Growth signals

Chromosome Alterations

• Deletion

• Duplication

• Inversion

• Translocation

Cellular Respiration Pathways

Glycolysis

Breaks down glucose into pyruvate; produces ATP and NADH.

$\text{Glucose} \rightarrow 2\text{Pyruvate} + 2\text{ATP} + 2\text{NADH}$

Citric Acid Cycle

Completes glucose breakdown; produces CO2, ATP, NADH, FADH2.

$2\text{Acetyl-CoA} \rightarrow 4\text{CO}_2 + 2\text{ATP} + 6\text{NADH} + 2\text{FADH}_2$

Oxidative Phosphorylation

Uses electron transport chain and chemiosmosis to generate ATP.

$\text{NADH} + \text{FADH}_2 \rightarrow \text{ATP}$

Cell Division and Genetics

Phases of Mitosis and Meiosis

• Mitosis: Prophase, Metaphase, Anaphase, Telophase

• Meiosis: Meiosis I (Prophase I, Metaphase I, etc.), Meiosis II

Cancer and the Cell Cycle

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

Genetic Variability in Meiosis

• Crossing over

• Independent assortment

• Random fertilization

Sex Determination

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

Enzyme Kinetics Lab

Results typically show how substrate concentration, pH, and temperature affect enzyme activity.

Summary Table: Tissue and Cell Types

Type	Structure	Function	Location
Squamous Epithelium	Flat	Diffusion	Lungs
Cuboidal Epithelium	Cube-shaped	Secretion	Kidney
Columnar Epithelium	Tall	Absorption	Intestine
Skeletal Muscle	Striated	Voluntary movement	Limbs
Smooth Muscle	Non-striated	Involuntary movement	Intestines
Cardiac Muscle	Striated	Heart contraction	Heart

Summary Table: Cellular Respiration Comparison

Process	Oxygen Required	ATP Yield	End Products
Aerobic Respiration	Yes	~36-38	CO2, H2O
Anaerobic Respiration	No	~2	Lactic acid or ethanol

Additional info: Academic context was added to expand brief points and clarify concepts for exam preparation.