Core Concepts in Cellular Processes and the Integumentary System

Cellular Processes

Chromosomes and Cell Division

Understanding the structure and function of chromosomes is fundamental to cell division and inheritance. Chromosomes carry genetic information and are essential for the proper distribution of DNA during cell division.

• Homologous Chromosomes: Chromosome pairs, one from each parent, that are similar in shape, size, and genetic content.

• Chromatids: Each chromosome consists of two identical sister chromatids joined at the centromere after DNA replication.

• Sister Chromatids: The two identical halves of a duplicated chromosome.

• Centromere: The region where sister chromatids are joined and where spindle fibers attach during cell division.

Mitosis vs. Meiosis vs. Interphase

Mitosis and meiosis are two types of cell division, while interphase is the phase where the cell prepares for division.

• Phases of Mitosis/Meiosis: Prophase, Metaphase, Anaphase, Telophase (Meiosis includes two rounds: Meiosis I and II).

• Microscopic Observation: Chromosomal changes can be observed under a light microscope during these phases.

• Somatic Cells: Undergo mitosis for growth and repair.

• Chromosomal Number: Mitosis maintains chromosome number; meiosis halves it for gamete formation.

• Crossing Over: Occurs during prophase I of meiosis, increasing genetic diversity.

Glucose Metabolism (Aerobic Metabolism/Cellular Respiration)

Cellular respiration is the process by which cells extract energy from glucose. It includes glycolysis, the Krebs cycle, and the electron transport chain (ETC).

• Aerobic vs. Anaerobic: Aerobic requires oxygen; anaerobic does not.

• Coenzyme A: Carries acetyl groups into the Krebs cycle.

• Enzymes: Specific enzymes catalyze each step of metabolism.

• ETC Location: Inner mitochondrial membrane.

• Oxygen Use: Oxygen is the final electron acceptor in the ETC.

Oxidation and Reduction (Redox Reactions)

Redox reactions are essential for energy transfer in cells.

• Oxidation:

  1. Combination of a substance with oxygen.

  2. Loss of electrons or increase in oxidation state.

  3. Decrease in positive valence or increase in negative valence by gaining electrons.

  4. Hydrogen is combined with a compound or oxygen is removed.

• Reduction:

  1. Decrease in positive valence or increase in negative valence by gaining electrons.

  2. Hydrogen is combined with a compound or oxygen is removed.

Phosphorylation

Phosphorylation is the addition of a phosphate group to a molecule, crucial for energy transfer.

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

• Oxidative Phosphorylation: ATP synthesis via the ETC.

• ATP Synthesis: $ADP + P_i \rightarrow ATP$

Hydrolysis/Dehydration Synthesis

These are chemical reactions involved in breaking down and building up biomolecules.

• Hydrolysis: Breaking bonds by adding water.

• Dehydration Synthesis: Forming bonds by removing water.

Chemiosmosis

Chemiosmosis is the movement of ions across a semipermeable membrane, generating ATP.

• Definition: Movement of hydrogen ions to produce ATP via ATP synthase.

Glycogenolysis and Gluconeogenesis

These processes regulate glucose levels in the body.

• Glycogenolysis: Breakdown of glycogen to glucose.

• Gluconeogenesis: Formation of glucose from non-carbohydrate sources, mainly in the liver.

Beta-Oxidation

Beta-oxidation is the process of breaking down fatty acids for energy.

• Definition: Successive removal of two-carbon fragments from fatty acids.

Lactic Acid Build-Up

Lactic acid accumulates during anaerobic metabolism, especially in muscle cells.

• Condition: Occurs when oxygen is limited and pyruvate is converted to lactic acid.

Sodium-Potassium Pump

The sodium-potassium pump maintains cellular ion gradients.

• Function: Transports 3 Na+ out and 2 K+ into the cell per ATP hydrolyzed.

• Equation: $3\text{Na}^+_{\text{in}} + 2\text{K}^+_{\text{out}} + ATP \rightarrow 3\text{Na}^+_{\text{out}} + 2\text{K}^+_{\text{in}} + ADP + P_i$

Integumentary System

• Types of Skin Cancer

Skin cancer arises from uncontrolled cell growth in the skin. The most common types are discussed in class.

• Most Common: Basal cell carcinoma, squamous cell carcinoma, melanoma.

• Origin: Where cancers arise in the skin layers.

Skin Color and Healing

Skin color is determined by melanin, hemoglobin, and carotene. Healing differs between deep and epithelial wounds.

• Normal vs. Abnormal: Variations in pigmentation and healing responses.

• Deep vs. Epithelial Healing: Deep wounds involve dermis; epithelial wounds are superficial.

Skin Layers

The skin consists of multiple layers, each with distinct functions.

• Epidermis: Outermost layer, provides protection.

• Dermis: Middle layer, contains connective tissue, blood vessels, and nerves.

• Thick vs. Thin Epidermis: Thick skin (palms, soles) has more layers than thin skin.

Glands and Cells in the Skin

Various glands and cell types contribute to skin function.

• Glands: Sebaceous (oil), sweat (eccrine and apocrine).

• Cells: Keratinocytes, melanocytes, Langerhans cells, Merkel cells.

Rules of Nines

The "Rules of Nines" is a method for estimating the extent of burns.

• Application: Divides the body into sections, each representing 9% (or multiples) of total body surface area.

Burns: Types, Signs, and Dangers

Burns are classified by depth and severity.

• Degrees: First (superficial), second (partial thickness), third (full thickness).

• Signs: Redness, blistering, charring.

• Dangers: Infection, fluid loss, shock.

Skin Lesions: ABCD's

The ABCD rule helps identify malignant melanoma.

• A: Asymmetry

• B: Border irregularity

• C: Color variation

• D: Diameter greater than 6 mm

Goose Bumps

Goose bumps are caused by contraction of arrector pili muscles in response to cold or emotional stimuli.

Skin Structure Diagram

The following table summarizes the main structures found in the skin, as illustrated in the provided image:

Layer	Main Structures	Functions
Epidermis	Stratum corneum, Stratum basale	Protection, barrier to pathogens
Dermis	Blood vessels, nerves, hair follicles, sweat glands	Sensation, thermoregulation, support
Hypodermis	Adipose tissue, larger blood vessels	Insulation, energy storage
Accessory Structures	Hair shaft, sebaceous gland, arrector pili muscle	Protection, lubrication, response to stimuli

Hair Bulb Components

Be able to label and identify the components of a hair bulb, including the hair follicle, papilla, and associated structures as shown in the Integumentary System PowerPoint.

Additional info: Academic context and definitions have been expanded for clarity and completeness.