Cell Structure and Function

Cell Structure and Function

• Cell membrane: semi-permeable, allows certain substances to pass through
• Cell wall: provides support and protection, found in plant cells
• Cytoplasm: jelly-like substance inside cell membrane, site of metabolic reactions
• Nucleus: controls cell growth and reproduction, contains DNA
• Mitochondria: generates energy for cell through cellular respiration
• Endoplasmic reticulum (ER): involved in protein synthesis and transport
• Ribosomes: site of protein synthesis
• Lysosomes: contains digestive enzymes, breaks down waste and foreign substances

Cell Division

• Mitosis: process of cell division, results in two daughter cells identical to parent cell
  • Interphase: cell grows and prepares for division
  • Prophase: chromatin condenses, nuclear envelope breaks down
  • Metaphase: chromosomes line up at center of cell
  • Anaphase: sister chromatids separate
  • Telophase: nuclear envelope reforms, chromatin uncoils
  • Cytokinesis: cytoplasm divides, resulting in two daughter cells
• Meiosis: process of gamete formation, results in four daughter cells with unique genetic combinations
  • Meiosis I: similar to mitosis, but with crossing over and independent assortment
  • Meiosis II: similar to mitosis, but with separation of sister chromatids

Genetics

• Mendel's Laws:
  • Law of Segregation: each pair of alleles separates during gamete formation
  • Law of Independent Assortment: alleles for different genes are sorted independently
  • Law of Dominance: dominant allele will be expressed over recessive allele
• Inheritance Patterns:
  • Autosomal dominant: dominant allele will be expressed, even if one copy is present
  • Autosomal recessive: recessive allele will be expressed only if two copies are present
  • Sex-linked: genes located on sex chromosomes, exhibit unique inheritance patterns
• Mutations: changes in DNA sequence, can result in changes to protein function or structure

Evolution

• Evidence for Evolution:
  • Fossil Record: fossilized remains of ancient organisms
  • Comparative Anatomy: similar structures in different species
  • Molecular Biology: similarities in DNA and protein sequences
• Mechanisms of Evolution:
  • Natural Selection: process by which best-adapted individuals are more likely to survive and reproduce
  • Genetic Drift: random change in allele frequency
  • Gene Flow: movement of genes from one population to another
  • Mutation: change in DNA sequence

Ecosystems

• Energy Flow:
  • Producers: convert sunlight into energy through photosynthesis
  • Consumers: obtain energy by consuming other organisms
  • Decomposers: break down organic matter, releasing nutrients
• Nutrient Cycles:
  • Carbon Cycle: carbon is exchanged between atmosphere, oceans, and land
  • Nitrogen Cycle: nitrogen is converted between forms, available for use by organisms
  • Water Cycle: water is cycled between atmosphere, oceans, and land

Biodiversity

• Species: group of organisms that can interbreed and produce fertile offspring
• Population: group of individuals of the same species living in a specific area
• Community: group of populations of different species living in a specific area
• Ecosystem: community of organisms and their physical environment
• Biodiversity: variety of species, ecosystems, and genes in an ecosystem or planet

Cell Structure and Function

• Cell membrane has selective permeability, regulating the flow of substances in and out of the cell.
• Cell wall provides structural support and protection, characteristic of plant cells.
• Cytoplasm is a jelly-like substance where metabolic reactions occur, allowing for cell growth and maintenance.
• Nucleus controls cell growth and reproduction, housing DNA, the genetic material.
• Mitochondria generate energy for the cell through cellular respiration, a crucial process for cell survival.
• Endoplasmic reticulum (ER) plays a central role in protein synthesis and transport, facilitating cellular communication.
• Ribosomes are the site of protein synthesis, responsible for creating essential proteins.
• Lysosomes contain digestive enzymes, breaking down waste and foreign substances, maintaining cellular hygiene.

Cell Division

• Mitosis is the process of cell division, resulting in two daughter cells identical to the parent cell.
• Interphase is the stage where the cell grows and prepares for division.
• Prophase involves chromatin condensation and nuclear envelope breakdown, marking the onset of cell division.
• Metaphase sees chromosomes align at the center of the cell, ensuring proper segregation.
• Anaphase involves the separation of sister chromatids, a crucial step in Genome replication.
• Telophase is characterized by nuclear envelope reformation and chromatin uncoiling, reestablishing cellular order.
• Cytokinesis is the final stage, where the cytoplasm divides, resulting in two daughter cells.

Genetics

• Mendel's Laws of Inheritance include:
  • Law of Segregation: each pair of alleles separates during gamete formation, ensuring genetic diversity.
  • Law of Independent Assortment: alleles for different genes are sorted independently, increasing genetic variation.
  • Law of Dominance: dominant alleles will be expressed over recessive alleles, influencing phenotype.
• Inheritance Patterns include:
  • Autosomal Dominant: dominant alleles will be expressed, even if one copy is present.
  • Autosomal Recessive: recessive alleles will be expressed only if two copies are present.
  • Sex-Linked: genes located on sex chromosomes, exhibiting unique inheritance patterns.

Evolution

• Evidence for Evolution includes:
  • Fossil Record: fossilized remains of ancient organisms, providing chronological records of evolutionary changes.
  • Comparative Anatomy: similar structures in different species, highlighting shared evolutionary history.
  • Molecular Biology: similarities in DNA and protein sequences, revealing molecular connections.
• Mechanisms of Evolution include:
  • Natural Selection: the process by which best-adapted individuals are more likely to survive and reproduce.
  • Genetic Drift: random changes in allele frequency, influencing population dynamics.
  • Gene Flow: movement of genes from one population to another, promoting genetic exchange.
  • Mutation: changes in DNA sequence, potentially leading to changes in protein function or structure.

Ecosystems

• Energy Flow involves:
  • Producers: converting sunlight into energy through photosynthesis.
  • Consumers: obtaining energy by consuming other organisms.
  • Decomposers: breaking down organic matter, releasing nutrients.
• Nutrient Cycles include:
  • Carbon Cycle: carbon is exchanged between atmosphere, oceans, and land.
  • Nitrogen Cycle: nitrogen is converted between forms, available for use by organisms.
  • Water Cycle: water is cycled between atmosphere, oceans, and land.

Biodiversity

• Species: a group of organisms that can interbreed and produce fertile offspring.
• Population: a group of individuals of the same species living in a specific area.
• Community: a group of populations of different species living in a specific area.
• Ecosystem: a community of organisms and their physical environment.
• Biodiversity: the variety of species, ecosystems, and genes in an ecosystem or planet, essential for maintaining ecological balance.

Learn about the different components of a cell, including the cell membrane, cell wall, cytoplasm, nucleus, mitochondria, and endoplasmic reticulum.