Cell Biology: Cell Structure

Cell Biology

Cell Structure:
- Plasma membrane: semi-permeable membrane that separates the cell from its environment
- Cytoplasm: jelly-like substance inside the cell membrane where metabolic processes occur
- Nucleus: contains genetic material (DNA)
- Mitochondria: organelles responsible for generating energy (ATP) through cellular respiration
- Endoplasmic reticulum (ER): organelle involved in protein synthesis and transport
- Lysosomes: organelles responsible for cellular digestion and recycling
Cell Functions:
- Metabolism: conversion of energy and nutrients into cellular components
- Photosynthesis: process by which cells convert light energy into chemical energy
- Cell signaling: communication between cells through signaling molecules
- Cell division: process by which cells reproduce and multiply

Genetics

DNA Structure:
- Double helix model: two complementary strands of nucleotides twisted together
- Nucleotides: building blocks of DNA, consisting of sugar, phosphate, and nitrogenous bases
Genetic Inheritance:
- Mendel's laws: principles of inheritance that describe how traits are passed down from generation to generation
- Genotype: genetic makeup of an individual
- Phenotype: physical expression of an individual's genotype
Genetic Variation:
- Mutations: changes in DNA sequence that can result in genetic variation
- Genetic drift: random change in the frequency of a gene in a population
- Gene flow: movement of genes from one population to another

Evolution

Mechanisms of Evolution:
- Natural selection: process by which individuals with favorable traits are more likely to survive and reproduce
- Genetic drift: random change in the frequency of a gene in a population
- Gene flow: movement of genes from one population to another
- Mutation: change in DNA sequence that can result in genetic variation
Evidence for Evolution:
- Fossil record: chronological record of ancient life forms
- Comparative anatomy: study of similarities and differences in body structure among organisms
- Molecular biology: study of similarities and differences in DNA and protein sequences among organisms

Lungs

Structure:
- Trachea: tube that connects the throat to the lungs
- Bronchi: tubes that branch off from the trachea and enter the lungs
- Alveoli: sacs where gas exchange occurs between the lungs and bloodstream
Function:
- Respiration: process of exchanging oxygen and carbon dioxide between the lungs and bloodstream
- Gas exchange: process by which oxygen is absorbed into the bloodstream and carbon dioxide is removed

Animal Cell

Characteristics:
- Eukaryotic: cells with a true nucleus and membrane-bound organelles
- Multicellular: composed of many cells that work together to form tissues and organs
- Heterotrophic: cells that obtain energy by consuming other organisms or organic matter
Unique Features:
- Lysosomes: organelles responsible for cellular digestion and recycling
- Centrioles: organelles involved in the formation of cilia and flagella
- Cilia: hair-like structures involved in movement and sensing the environment

Cell Biology

Cell Structure:
- Plasma membrane is semi-permeable, separating the cell from its environment and regulating what enters and leaves.
- Cytoplasm is the jelly-like substance inside the cell membrane where metabolic processes, such as protein synthesis and cellular respiration, occur.
- Nucleus contains genetic material (DNA) and is responsible for controlling cell growth and division.
- Mitochondria are organelles responsible for generating energy (ATP) through cellular respiration.
- Endoplasmic reticulum (ER) is involved in protein synthesis and transport, as well as lipid synthesis and detoxification.
- Lysosomes are organelles responsible for cellular digestion and recycling, breaking down and recycling cellular waste and foreign substances.
Cell Functions:
- Metabolism involves the conversion of energy and nutrients into cellular components, such as carbohydrates, proteins, and fats.
- Photosynthesis is the process by which cells convert light energy into chemical energy, using light, water, and carbon dioxide to produce glucose and oxygen.
- Cell signaling involves communication between cells through signaling molecules, such as hormones and neurotransmitters.
- Cell division is the process by which cells reproduce and multiply, resulting in two daughter cells with identical genetic material.

Genetics

DNA Structure:
- Double helix model consists of two complementary strands of nucleotides twisted together, with sugar and phosphate molecules making up the backbone.
- Nucleotides are the building blocks of DNA, consisting of sugar, phosphate, and one of four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
Genetic Inheritance:
- Mendel's laws describe how traits are passed down from generation to generation, including the law of segregation and the law of independent assortment.
- Genotype is an individual's genetic makeup, including all of their genes and alleles.
- Phenotype is an individual's physical expression of their genotype, resulting from the interaction of genes and environment.
Genetic Variation:
- Mutations involve changes in DNA sequence, which can result in genetic variation and affect the function of proteins and genes.
- Genetic drift is a random change in the frequency of a gene in a population, resulting in a loss of genetic variation.
- Gene flow is the movement of genes from one population to another, resulting in an increase in genetic variation.

Evolution

Mechanisms of Evolution:
- Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce, resulting in the adaptation of populations to their environment.
- Genetic drift is a random change in the frequency of a gene in a population, resulting in a loss of genetic variation.
- Gene flow is the movement of genes from one population to another, resulting in an increase in genetic variation.
- Mutation is a change in DNA sequence that can result in genetic variation and affect the function of proteins and genes.
Evidence for Evolution:
- Fossil record provides a chronological record of ancient life forms, showing the gradual changes and diversification of species over time.
- Comparative anatomy reveals similarities and differences in body structure among organisms, indicating a common ancestor.
- Molecular biology reveals similarities and differences in DNA and protein sequences among organisms, indicating a common ancestor.

Lungs

Structure:
- Trachea is the tube that connects the throat to the lungs, dividing into two primary bronchi that enter the lungs.
- Bronchi are the tubes that branch off from the trachea and enter the lungs, eventually dividing into smaller airways.
- Alveoli are the sacs where gas exchange occurs between the lungs and bloodstream, allowing for the exchange of oxygen and carbon dioxide.
Function:
- Respiration involves the process of exchanging oxygen and carbon dioxide between the lungs and bloodstream.
- Gas exchange is the process by which oxygen is absorbed into the bloodstream and carbon dioxide is removed, occurring in the alveoli.

Animal Cell

Characteristics:
- Eukaryotic cells have a true nucleus and membrane-bound organelles, which are characteristic of animal cells.
- Multicellular organisms are composed of many cells that work together to form tissues and organs.
- Heterotrophic cells obtain energy by consuming other organisms or organic matter.
Unique Features:
- Lysosomes are responsible for cellular digestion and recycling, breaking down and recycling cellular waste and foreign substances.
- Centrioles are involved in the formation of cilia and flagella, which are hair-like structures involved in movement and sensing the environment.
- Cilia are hair-like structures involved in movement and sensing the environment, such as in the movement of mucus out of the lungs.