Cell Biology and Genetics Overview

Cell Biology

• Cell Theory:

  • All living organisms are composed of cells.
  • The cell is the basic unit of life.
  • All cells arise from pre-existing cells.

• Types of Cells:

  • Prokaryotic: Lack a nucleus, smaller, simpler (e.g., bacteria).
  • Eukaryotic: Have a nucleus, larger, more complex (e.g., plants, animals, fungi).

• Cell Organelles:

  • Nucleus: Contains DNA, controls cell activities.
  • Mitochondria: Powerhouse of the cell, produces energy (ATP).
  • Ribosomes: Synthesize proteins.
  • Endoplasmic Reticulum (ER):
    • Rough ER: Studded with ribosomes, involved in protein synthesis.
    • Smooth ER: Lipid synthesis, detoxification.
  • Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
  • Lysosomes: Contain digestive enzymes to break down waste.

Genetics

• DNA Structure:

  • Double helix composed of nucleotides (A, T, C, G).
  • Base pairing: A-T and C-G.

• Genes and Chromosomes:

  • Gene: Unit of heredity, a segment of DNA.
  • Chromosomes: Structures that carry genetic information, humans have 46 (23 pairs).

• Mendelian Genetics:

  • Principles of inheritance: Dominance, segregation, independent assortment.
  • Punnett squares used to predict offspring genotypes.

• Mutations:

  • Changes in DNA sequence; can be beneficial, neutral, or harmful.

Evolution

• Natural Selection:

  • Mechanism by which individuals with advantageous traits survive and reproduce.

• Speciation:

  • Process by which new species arise; can occur through allopatric (geographic) or sympatric (same area) mechanisms.

• Evidence of Evolution:

  • Fossil record, comparative anatomy, molecular biology, and biogeography.

Ecology

• Levels of Organization:

  • Individual, population, community, ecosystem, biome, biosphere.

• Ecosystem Components:

  • Biotic Factors: Living components (plants, animals, microbes).
  • Abiotic Factors: Non-living components (water, soil, climate).

• Food Chains and Webs:

  • Energy flow: Producers (autotrophs) → Consumers (heterotrophs) → Decomposers.
  • Trophic levels: Primary, secondary, tertiary consumers.

• Biogeochemical Cycles:

  • Cycles of matter (e.g., water, carbon, nitrogen) through ecosystems.

Human Biology

• Major Systems:

  • Circulatory, respiratory, digestive, nervous, muscular, skeletal, endocrine, immune, reproductive.

• Homeostasis:

  • The body's ability to maintain stable internal conditions despite external changes.

• Metabolism:

  • Sum of all chemical reactions in the body, including catabolism (breaking down) and anabolism (building up).

Plant Biology

• Photosynthesis:

  • Process by which plants convert sunlight into chemical energy (glucose).
  • Occurs in chloroplasts, involving chlorophyll.

• Plant Structures:

  • Roots: Absorb water and nutrients.
  • Stems: Support and transport.
  • Leaves: Main site of photosynthesis.

• Reproduction:

  • Asexual (cloning, vegetative propagation) and sexual (seed formation via flowers).

Cell Biology

• Cell Theory: Fundamental principle stating that all living organisms are made up of cells, which are the basic units of life, and originate from pre-existing cells.
• Types of Cells:
  • Prokaryotic: Cells without a nucleus, generally smaller and simpler, exemplified by bacteria.
  • Eukaryotic: Cells with a nucleus, larger and more complex, including plants, animals, and fungi.
• Cell Organelles:
  • Nucleus: Repository of DNA, regulating cellular activities.
  • Mitochondria: Known as the cell's powerhouse, responsible for ATP production and energy.
  • Ribosomes: Sites of protein synthesis within the cell.
  • Endoplasmic Reticulum (ER):
    • Rough ER has ribosomes and is key for protein synthesis.
    • Smooth ER is involved in lipid synthesis and detoxification.
  • Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
  • Lysosomes: Contain enzymes for digestion and degradation of waste materials.

Genetics

• DNA Structure: Composed of a double helix formed by nucleotides (adenine, thymine, cytosine, guanine) with specific base pairing (A-T and C-G).
• Genes and Chromosomes:
  • Genes act as hereditary units, segments of DNA that code for proteins.
  • Humans possess 46 chromosomes organized into 23 pairs, containing genetic information.
• Mendelian Genetics: Focuses on independent assortment, segregation, and dominance; employs Punnett squares for genotype prediction.
• Mutations: Variations in DNA sequences that can be categorized as beneficial, neutral, or harmful to organisms.

Evolution

• Natural Selection: The process by which individuals with advantageous traits have higher survival and reproductive rates, influencing species' evolution.
• Speciation: The formation of new species, which can occur through:
  • Allopatric Speciation: Speciation due to geographical barriers.
  • Sympatric Speciation: Speciation occurring without geographical separation.
• Evidence of Evolution: Signified by fossil records, comparative anatomy, molecular biology, and biogeographical distribution.

Ecology

• Levels of Organization: Hierarchical structure from individual organisms to populations, communities, ecosystems, biomes, and the biosphere.
• Ecosystem Components:
  • Biotic Factors: Include all living entities, such as plants, animals, and microbes.
  • Abiotic Factors: Non-living elements like water, soil, and climate.
• Food Chains and Webs: Illustrate energy flow:
  • Begins with producers (autotrophs), followed by consumers (heterotrophs), and ends with decomposers.
  • Trophic levels identify primary, secondary, and tertiary consumers.
• Biogeochemical Cycles: Describe the movement of essential substances (water, carbon, nitrogen) through biological and geological systems.

Human Biology

• Major Systems: Include circulatory, respiratory, digestive, nervous, muscular, skeletal, endocrine, immune, and reproductive systems.
• Homeostasis: The ability of the human body to maintain stable internal conditions despite external environmental changes.
• Metabolism: Encompasses all biochemical reactions in the body, divided into:
  • Catabolism: The breakdown of molecules for energy.
  • Anabolism: The synthesis of complex molecules from simpler ones.

Plant Biology

• Photosynthesis: The process where plants utilize sunlight to convert carbon dioxide and water into glucose, primarily occurring in chloroplasts containing chlorophyll.
• Plant Structures:
  • Roots: Responsible for water and nutrient absorption.
  • Stems: Provide structural support and transport vital substances.
  • Leaves: Main site where photosynthesis occurs, maximizing sunlight capture.
• Reproduction: Includes both asexual methods (like cloning and vegetative propagation) and sexual reproduction through flower and seed formation.

This quiz covers essential concepts in cell biology and genetics, including cell theory, types of cells, key organelles, and the structure of DNA. Test your knowledge on the fundamental building blocks of life and the genetic material that codes for traits.