HG 241_1_default

Chapter 1: Introduction

Overview

• Focus on cells and cell division rather than introductory genetics.

• The course will cover:

  • Basics of genetics: genes, DNA, proteins.

  • Applications of genetics after mid-semester break (e.g., cancer, reproductive technologies).

Cells and Cell Division

• Two Main Types of Cells:

  • Eukaryotic: Multi-cellular organisms (humans, plants, animals).

  • Prokaryotic: Single-celled organisms (bacteria).

• Key Differences:

  • Prokaryotes: single circular chromosome, simpler structure, minimal organelles.

  • Eukaryotes: linear chromosomes inside a nucleus, numerous organelles with specific functions.

Shared Structures

• All cells have:

  • Cell membrane: encloses cell contents.

  • Ribosomes: sites for protein synthesis.

Components of a Eukaryotic Cell

• Eukaryotic Cell Structure:

  • Plasma Membrane: outer layer.

  • Cytoplasm: fluid where organelles reside.

  • Nucleus: contains DNA in the form of chromosomes.

• Electron Microscope Images: Referenced for visual understanding.

Evolution of Cells

• History: Eukaryotic cells evolved from prokaryotic cells over billions of years through symbiotic relationships.

• Development: Key to multicellularity was the engulfment of smaller prokaryotes by larger cells, evolving into organelles.

Chapter 2: Mitochondria And Cell

Mitochondria

• Energy-producing organelles; number varies by cell type (e.g., more in heart cells).

• Contain own circular DNA, different from nuclear DNA.

• Responsible for aerobic respiration.

Cell Components

• Cytoplasm: Thick solution with organelles and structural proteins.

• Endoplasmic Reticulum (ER): Network of membranes; two types:

  • Rough ER: has ribosomes, processes proteins.

  • Smooth ER: synthesizes and stores lipids/steroids.

Golgi Apparatus

• Processes and packages proteins from the rough ER.

• Produces lysosomes for cellular cleanup.

Chapter 3: Types Of Cell

Chromosomes

• Human Chromosomes: 23 pairs, 22 autosomes and 1 pair of sex chromosomes (XX or XY).

• Karyotyping: Used to study chromosome structure and number.

• Chromatin: Loosely organized DNA during non-dividing phases.

Disorders Related to Organelles

• Golgi Apparatus Dysfunction: Linked to achondrogenesis (skeletal disorders) and Alzheimer’s.

• Tay-Sachs Disease: Caused by lysosome malfunction, leading to fat buildup in cells.

Chapter 4: New Daughter Cell

Cell Cycle Overview

• Phases: Divided into Interphase (cell growth), Mitosis (cell division), and Cytokinesis (final division).

• Interphase: Contains G1, S (DNA replication), and G2 (final preparations).

• Each phase is tailored to cell function and type.

Mitosis Stages

• Prophase: DNA condenses, nuclear envelope breaks down.

• Metaphase: Chromosomes align at the cell center.

• Anaphase: Chromosomes are pulled apart.

• Telophase: Nuclear envelope reforms around separated chromosomes.

Cytokinesis

• Final separation of the cytoplasm into two new cells.

Chapter 5: Create New Cells

Mitosis Overview

• Mitosis creates two identical daughter cells, essential for growth and maintenance.

• Example of live-cell division observed using fluorescent microscopy.

Division Rates

• Different cells divide at differing rates based on need (e.g., bone marrow vs. neurons).

Chapter 6: End The Cell

Meiosis Overview

• Produces four genetically diverse cells (haploid) from one diploid cell.

• Essential for gamete formation, involves genetic recombination in prophase one.

Terms to Know

• Diploid: Cells with two copies of each chromosome (somatic cells).

• Haploid: Cells with one copy of each chromosome (gametes).

Chapter 7: Conclusion

Genetic Variation and Adaptation

• Meiosis ensures genetic diversity crucial for evolution.

• Variability among gametes contributes to adaptability to environments, demonstrated in skin color adaptation.

Overall Significance

• Understanding cell division processes is critical for grasping genetics and its applications in health and disease.