Cytology & Mitosis: Study Guide for ANP College Students

Week 4: Cytology & Mitosis

Introduction

This study guide covers the essential concepts of cytology (the study of cells) and mitosis (cell division), focusing on cell organelles, cell types, and the phases of mitosis. These topics are foundational for understanding the cellular level of organization in anatomy and physiology.

Mission Dashboard: Deliverables & High-Yield Topics

Overview

• Homework: Complete all questions and cell diagrams, and identify mitosis phases.

• Lab Manual Readings: Focus on cell organelles and cell structure.

• High-Yield Topics: Organelle functions, cell types (prokaryote vs. eukaryote), and mitosis phases (PMAT).

The Control Center & Builders

Nucleus, Nucleolus, and Ribosomes

The nucleus, nucleolus, and ribosomes are critical for genetic information storage, processing, and protein synthesis.

• Nucleus: Stores DNA and directs cell activities. Found in all eukaryotes.

• Nucleolus: Located inside the nucleus; makes rRNA and assembles ribosomes.

• Ribosomes: Sites of protein synthesis; found free-floating or bound to rough ER in all cells (including prokaryotes).

The Factory: Endoplasmic Reticulum (ER)

Rough ER (RER) vs. Smooth ER (SER)

The endoplasmic reticulum is divided into two types, each with distinct functions:

• Rough ER (RER): Studded with ribosomes; synthesizes proteins.

• Smooth ER (SER): Lacks ribosomes; synthesizes lipids and detoxifies substances.

Mnemonic: Rough ER has "ribs" (ribosomes); Smooth ER does not.

Power & Waste Management

Mitochondria, Lysosomes, and Peroxisomes

These organelles manage energy production and waste disposal in the cell.

• Mitochondria: The "powerhouse" of the cell; produces ATP via cellular respiration.

• Lysosomes: Digest waste; found only in animal cells. Mnemonic: Lysosomes = Lysol (cleaning).

• Peroxisomes: Detox centers; break down fatty acids and hydrogen peroxide.

Logistics & Framework

Golgi Apparatus, Cytoskeleton, and Centrioles

These structures are responsible for protein packaging, cell shape, and division.

• Golgi Apparatus: Modifies, packages, and ships proteins ("gift wrapping/post office").

• Cytoskeleton: Provides scaffolding for shape, movement, and transport.

• Centrioles: Organize spindle fibers for cell division; found only in animal cells.

The Great Divide: Prokaryote vs. Eukaryote

Key Differences

Cells are classified as prokaryotic or eukaryotic based on the presence of membrane-bound organelles.

• Prokaryotes: No nucleus (nucleoid region only), small ribosomes, no membrane-bound organelles.

• Eukaryotes: Membrane-bound nucleus, larger ribosomes, and many membrane-bound organelles.

Critical Alert: Never say prokaryotes have organelles—they lack membrane-bound ones.

Identification Guide: Plant vs. Animal Cells

Major Features

Plant and animal cells can be distinguished by several structural features:

Feature	Animal	Plant
Shape	Irregular / Round	Fixed / Rectangular
Cell Wall	❌ NO	✔ YES (Cellulose)
Chloroplasts	❌ NO	✔ YES
Central Vacuole	Small / Temporary	Large Central Vacuole
Centrioles	✔ YES	❌ NO

The Cell Cycle Clock

Phases of the Cell Cycle

The cell cycle consists of interphase (G1, S, G2) and the M phase (mitosis and cytokinesis).

• G1: Growth and protein synthesis.

• S Phase: DNA replication (chromosomes duplicate).

• G2: Preparation for division and error checking.

• M Phase: Mitosis (nuclear division) and cytokinesis (cytoplasmic division).

M-Phase: Mitosis (PMAT)

Overview of Mitosis

Mitosis is the process of nuclear division, distinct from cytokinesis. The phases of mitosis are:

• Prophase

• Metaphase

• Anaphase

• Telophase

PMAT: The Setup & The Lineup

• Prophase: Chromosomes condense and become visible; nuclear envelope breaks down.

• Metaphase: Chromosomes line up at the cell's equator (metaphase plate).

PMAT: The Split & The Reset

• Anaphase: Sister chromatids separate and are pulled to opposite poles.

• Telophase: Nuclear envelopes reform; chromosomes decondense; two nuclei form.

Cytokinesis: The Physical Split

Animal vs. Plant Cells

Cytokinesis is the division of the cytoplasm, distinct from mitosis (nuclear division).

• Animal Cells: Cleavage furrow pinches the cell in two (like a drawstring bag).

• Plant Cells: Cell plate forms, which becomes the new cell wall.

Danger Zone: Common Quiz Mistakes

Frequent Errors & Fixes

• Confusing Factories: Mixing up RER (protein) and SER (lipid).

• Mitosis Misconception: Mitosis is only nuclear division, not the whole cell division.

• Prokaryote Error: Prokaryotes do not have membrane-bound organelles.

• Phase Confusion: Metaphase = line up; Anaphase = pull apart.

High-Yield Review: Organelles

Key Organelle Functions

• ATP Production: Mitochondria

• Ribosome Assembly: Nucleolus

• RER vs. SER: RER has ribosomes (protein synthesis); SER does not (lipid synthesis).

• Plasma Membrane: Selective barrier; controls entry and exit of substances.

High-Yield Review: Processes & Structure

Key Processes & Differences

• Plant vs. Animal Cells: Cell wall, chloroplasts, central vacuole (plant only).

• Prokaryotes: No mitochondria or membrane-bound organelles.

• Mitosis vs. Cytokinesis: Mitosis = nuclear division; Cytokinesis = cytoplasmic division.

• Sister Chromatid Separation: Occurs during anaphase.

Lab Day Preview: What You'll See

Microscopy Observations

• Cheek Cells (Animal): Observe cell slides and identify mitosis phases.

• Onion Root Tip (Plant/Mitosis): Most cells will be in interphase (90%).