The Cell
Introduction
Cell theory:
Cells are the structural "building blocks" of all plants and animals.
The division of preexisting cells produces cells.
Cells are the smallest structural units that perform all vital functions.
Introduction
Cells fall into two categories:
Sex cells (germ cells or reproductive cells) are the sperm in males and oocyte in females.
Somatic cells are all of the other cells in the body that are not sex cells.
The Study of Cells
The study of cells is cytology:
Light microscopy
Transmission electron microscopy
Scanning electron microscopy
Cellular Anatomy
Cellular Anatomy
The Cell Membrane
The Cell Membrane
Four major functions of the cell membrane can be described:
Physical isolation
Regulation of exchange with the environment
Sensitivity/Communication
Structural support
Membrane Permeability: Passive Processes
Diffusion
Osmosis
Facilitated
Diffusion
Membrane Permeability: Active Processes
Active transport uses enzymes and carrier proteins:
Ions pumps
Na+, Ca2+, Mg2+, K+
Ion pumps
are specific.Exchange pumps.
Na+, K+
Membrane Permeability: Active Processes
Membrane Permeability: Active Processes
Membrane Permeability: Active Processes
Cytoplasm
Material inside the cell.
Cytosol / intracellular fluid
It is high in potassium ions.
It contains an overall negative charge.
Transmembrane potential
High concentration of proteins.
Organelles
Nonmembranous Organelles
The cytoskeleton:
Microfilaments: Actin
Intermediate filaments
Thick
filaments: MyosinMicrotubules
Microvilli
Nonmembranous Organelles
Nonmembranous Organelles
Centrioles
Cilia
Flagella
Nonmembranous Organelles
Ribosomes:
RNA & Protein
Free ribosomes:
Float in the cytoplasm
Fixed ribosomes
:Are attached to the endoplasmic reticulum
Membranous Organelles
Mitochondria are double membraned organelles.
Cristae
are the folds of the inner membraneInner fluid is the matrix.
Membranous Organelles
The nucleus is the control center of the cell.
Nucleoplasm
Nuclear envelope
Perinuclear space
Nuclear pores
Nuclear matrix
Membranous Organelles
Membranous Organelles: Nucleus
Chromosomes:
DNA wrapped
around proteins
called histones.Nucleosomes
Chromatin
Membranous Organelles
The ER has four major functions:
Synthesis of all classes of macromolecules
Storage of the manufactured molecules
Transport of substances from on area of the cell to another
Enzymes in the lumen of the ER provide detoxification
Membranous Organelles
Membranous Organelles
Golgi apparatus
Secretions.
Packaging of enzymes
Cell membrane maintenance
Membranous Organelles
Lysosome function
Phagosomes
Recycle organelles
Autolysis.
Intercellular Attachment
The Cell Life Cycle
DNA Replication
Interphase
Prophase
Metaphase and Anaphase
Telophase and Cytokinesis