Types of Cells
Prokaryotes |
"Before nucleus", doesn't contain a membrane bound nuceleus |
Eubacteria |
Prokaryote; True bacteria |
Archaea |
Prokaryote; Missing link between prokaryotic and Eukaryota cells |
Eukaryotes |
"True nucleus", contains a membrane bound nucleus |
Eukarya |
Eukaryotic; domain containing eukaryotes |
Eubacteria
- Small (650 nm)
- Contains cell wall, can be gram stained
- Organelles:
Nucleoid = Ring of DNA; plasmids
Cytosol = Jelly-like material
Ribosome = None-membrane bound, synthesizes proteins (rRNA)
- Gram stain is purple = positive, thick cell wall
- Gram stain is pink = negative, thin cell wall |
Archaea
- Discovered in 1977
- Cannot be gram stained
- Similar organelles as eubacteria, but the cell wall is different
- Contains histones (packaging molecules, what chromosomes wrap around)
- Contains chromosomes, a eukaryotic characteristic |
Eukarya
- Eukaryotic cells
- Organelles:
Nucleus
Nucleolus
Membrane bound organelles
Ribosomes |
History of Cells
1665; Robert Hooke |
Named cells |
1830s; T. Schwann |
Stated that cells make up all living things |
1850s; Mettius Schleiden |
Stated "...the vital process of individual cells must form first and is the basis of life" |
Late 1850s; Rudolf Virchow |
Established the cell theory with other scientists |
Cell Theory
1) All living things are made of cells, cells are the unit of life for all living things |
2) Cells arise from preexisting cells |
Plasma Membrane
Phospholipid bilayer formed by the presence of water due to hydrophobic interaction
Function = control what goes in and out of the cell
Proteins in Cell Membrane
Integral Protein |
Proteins that go completely through the protein |
Peripheral Protein |
Surface of the membrane, trigger/receptor proteins = transports/responds |
Glycoprotein/Glycolipid |
used for cell recognition |
Cholesterol |
Keeps the fluid-like characteristics of the membrane |
Gastrula
Zygote - Fertilized egg
Blastula - Hollow sphere of germ/stem cells
Homeostasis
Homeostasis |
Ability for a cell/organism to maintain its internal environment |
Apoptosis |
Programmed cell death, based on genetics |
Poikilothermic |
Body temperature fluctuates |
Homothermic |
Constant body temperature |
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Diffusion
Movement of a particle/atom/molecule using a concentration gradient, move from an area of high concentration to an area of low concentration
Osmosis
Movement of water using a concentration of water, moving from an area of high water potential to an area of low water potential
Facilitated Diffusion/Passive Transport
Diffusion of a large particle (ex. starch), requires an integral protein but no energy
Active Transport
Also called "pumps", pumps material against concentration gradient (low to high), requires a protein and energy
Endocytosis and Exocytosis
Other transport mechanisms
Other Transport Mechanisms
Phagocytosis |
Used for large materials |
Pinacytosis |
Used for small materials |
Forms of exocytosis and endocytosis
Transport Terms
Hypertonic |
High concentration |
Hypotonic |
Low concentration |
Isotonic |
Equal concentration |
Crenate |
Cell shrinks |
Lysis |
Cell Explodes |
If a cell is hypertonic, the solution is hypotonic and vice versa
Hypertonic/Isotonic/Hypotonic
Methods of Nutritional Feeding
Heterotrophs |
Organisms consumes other organisms |
Autotrophs |
Organisms makes its own foods (photosynthesis) |
Chemoautotrophs |
Uses sulfur as a food source |
Organotrophs |
Uses organic compounds for food |
Lithrotrophs |
Uses inorganic compounds for food |
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Genetic Material
Nuclear Membrane
- Composed of phospholipids
- Has pores, allows mRNA to pass through
Nucleus
- Contains 2 types of DNA:
1) Chromosomes (present during cell division)
2) Chromatin (uncondensed DNA)
Nucleolus
- Not membrane-bound ( = no phospholipids)
- Just condensed DNA
- Function: synthesize rRNA (ribosomes) |
Organelles
Organelle |
Organ of the cell |
Cytosol |
Jelly-like material, cytosol + organelles = cytoplasm |
Golgi Apparatus |
Membrane bound; Function: Synthesize carbs, modify proteins & lipids |
Ribosome |
Not membrane bound; Function: Synthesize protein, composed of rRNA |
Endoplasmic Reticulum (ER) |
Membrane bound; Has two types: 1) Rough - Contains ribosomes, synthesizes proteins and lipids 2) Smooth - No ribosomes, synthesizes lipids |
Mitochondria |
Double membrane bound; Function: Provides 95% of the cell's energy |
Peroxisome |
Membrane bound; Function: Break down toxins |
Vacuoles |
Membrane bound; Function: Stores water, minerals, etc |
Lysosome |
Membrane bound; Function: Breakdown organelles and produce digestive enzymes, ONLY IN ANIMAL CELLS |
Cell Wall (Plants) |
Composed of cellulose & pectin (protein fiber) |
Chloroplast |
Double membrane; Function: Photosynthesis, ONLY IN PLANT CELLS |
Plastids |
Double membrane; Function: Store starch, ONLY IN PLANT CELLS |
Tonoplasts |
Membrane for large central vacuole (which is ~90% of of plant cells, holds water, ions, salts, and buffers) |
Chloroplast
Two reactions:
1) Light reaction (Thylakoid)
2) Dark reaction (Calvin cycle, stroma)
Mitochondria
- Provides 95% of a cell's energy
- Matrix: Krebs cycle
- Cristae: Electron transport chain (ETC)
Cytoskeleton
Found in all cells, Function: Support and hold shape of the cell, organelle placement, move things |
Microfilament |
7 nm thick, deals with muscle contractions (actin) |
Intermediate Filaments |
8-10 nm thick, holds cell shape |
Microtubules |
25 nm thick, moves chromosomes in cell division |
Other
Root Hairs |
Cytoplasm projections, Function: water absorption |
Alveoli |
Air sacs in the lungs, needs water for gas exchange between blood and the air sac |
Villi |
In small intestine, 1,500 microvilli on villi increases surface area |
What Happens Under These Conditions?
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Animal cell is in a hypertonic solution Cell crenates (gets smaller)
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Animal cell is in a hypotonic solution Cell lyse (lysis -> cell expands and explodes)
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Animal cell is under UV light Cell death, causes thymine dimers (thymine bonds with thymine in DNA)
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Radiation Cause ionization
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Growth hormones as a food additive Hormones are estrogen based, possibly causes delayed or early puberty
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Pesticide Also estrogen based, alligators don't develop sexual organs
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