OR:
1 nm: Molecules
10 nm: Cell Membrane
75 nm: Virus
100 nm: Macromolecules
1 mm(micrometer): Bacteria
3 mm: Organelles
10 mm: Cell
Surface area to volume ratio: *The rate of the metabolism of a cell is a function of its mass to volume ratio.* The more active a cell's metabolism, the more material must be exchanged if the cell is to continue to function. The smaller the cell, the more efficent it is. Larger cells require more energy, but their surface area to volume is closer to one, making them less efficent.
Cell Nucleus: A membrane enclosed organelle containing genetic information.
Possible outdated information:
All living things are made from cells, and all cells are created by other cells.
A virus is a non-cellular structure of DNA or RNA surrounded by a protein coat.
Unicellular organisms carry out all the functions of life
In multicellular organisms, all cells contain genes. By only expressing some of their genes, the cells in multicellular organisms differntiate to carry out specialized jobs.
A tissue is an integrated group oi cells that have a common structure and function.
An organ is a center of the body composed of several different types of tissue and carries out a bodily function.
An organ system is a group of organs the specialize in a certian function together.
1.2 Prokaryotic Cell Structure
Prokaryote: (pro before + karyon kernel) A cell that lacks any membrane bound organelles. Prokaryotes also belong to their own kingdom, bacteria and blue-green algee.
Ribosomes: Small cytoplasmic granules found in all cells. They are smaller than the ribosomes found in eukaryotic cells. They occur singly or in groups called polysomes. They are made of RNA and protein. They are important in protein synthesis. Produces protein for use inside cells.
Mesosomes: Resembles the mitocondria in eukaryotes. They are infoldings of the cell membrane and are important in/site of resperation. Primitive vacoules(deep furrows) to store food or waste.
Slime-Capsule: Surrounds the cell wall of bacteria, it helps to keep the cell from being digested or drying out. Keeps away predatory protazoam white blood cells and bacteriophages.
Flagellum: A small projection from a cell wall that propells a cell. It is an organelle. Flagullum are accanged around the cell in nine doublets with two single microtubules in the middle. This arrangement is known as the "9+2" pattern.
Cell Wall: Gives the cell it's shape, protects the cell and prevents the cell from absorbing too much water.
Cell Surface Membrane:Controls the movement of things in and out of the cell. Protects the organellesinside from the outside enviornment. It is made of phospholipids.
Plasmid: An extra-chromosomal, independantly replicating, small, circular DNA molecule. Enables production of antibiotics or resistance to anti-biotics.
Naked Nucleic Acid: Contains the hereditary information of the cell. It regulates protein production.
Cytoplasm: A gelatonus, semi-trasparent fluid that fills most cells.
Cytoskeleton: A structure that maintains the shape of the cell, protects the cell and enables motion, The cytoskeleton plays an important role in inter-cellular transport and cellular division.
1.3 Eukaryotic Cells
Vocabulary:
ATP: energy molecule used in active transport against the concentration gradient.
Centrioles: vital for reproduction (production of spindle fibres)
Chloroplast: contains chlorophyll and is present only in plant cells. Is involved in photosynthesis.
Concentration gradient: difference of concentration between two substances
Cytolysis: animal cell exploding
Cytoskleteon: maintains in cell shape
Endocytosis: food/liquid going into the cell
Endosymbiosis: The theory that mitochondria and chloroplasts are descended from specialized bacteria. This is because these organelles both contain their own DNA and this DNA is present in a single, continuous molecule, like the DNA of bacteria. Many of the enzymes contained in the cell membranes of bacteria are found in the mitochondrial membranes. Also, they both have their own ribosomes that resemble those of bacteria. Mitochondria can only be produced by mitochondria, like cells from cells. Probably these organelles used to be simple bacteria and were swallowed up by bigger bacteria who could not digest them. In turn these organelles provided the cell with energy in return for protection etc. and turned into an organelle.
Equilibrium: equal amounts moving in and out
Exocytosis: waste going out of the cell
Flaccid: animal cell shrinking
Golgi Apparatus: stacks of flattened membranous sacs. Packages secretions and manufactures lysosomes. Modifies and 'repacks' proteins.
Homeostasis: balance
Hypertonic: less water, more solute
Hypotonic: more water, less solute
Isotonic: equal amounts of water and solute
Lysosome: membranous sacs containing hyrolytic enzymes. Hyrolyze proteins and other matierals, including ingested bacteria, and also play a role in cell death by 'digesting' the whole cell.
Mitochondrion: (similar to mesosomes in prokaryotes) site of the most of the reactions of cellular respiration; power plants of the cell.
Nucleolus: stores RNA within the nucleus
Nucleus: large spherical structure surrounded by a double nuclear membrane; contains nucleolus and chromosomes. Control center of the cell; contains genetic material. An organelle that stores linear DNA.
Osmosis: movement of H2O in and out of cell
Phagocytsosis: endocytosis of food
Pinocytosis: endocytosis of liquid
Plant cell wall: contains cellulose which is strong tough material. This is important because cells of plants need more structure so that it doesn't move- the cell wall provides this. It also contains pits and plasmodesmata in the cell wall so that the plant cell can 'communicate' with other plant cells.
Plasmolysis: plant cell shrinking
Protein carriers: pumps (active) and channels (passive)
Ribosome: nonmembranous granules composed of RNA and protein- some are attached to ER. Manufacture proteins.
Rough endoplasmic reticulum: network of internal membranes extending through cytoplasm; forms system of tubes and vesicles. Rough sort contains ribosomes which stud the outer surfaces. Manufactures and transports proteins.
Smooth Endoplasmic reticulum: stores proteins, but does not have ribosomes
Turgid: plant cell turning stiff
Turgor pressure: pressure inside the cell
Vacuole: stores excess liquids
Two similarities between prokaryotic and eukaryotic:
both contain a cell membrane, two phospholipid sheets.
both contain the genetic information- that directs a cell's activities and enables it to reproduce.
Two differences between the eukaryotic nucleus and prokaryotic nuclear material:
in a prokaryotic cell, the genetic material is in the form of a large, circular molecule of DNA, with wihich a vaiety of proteins are loosely associated. This molecule is known as the chromosome. In eukaryotic cells, the DNA is linear, forming a number of distinct chromosomes; morover, it is tightly bound to special proteins known as histones, which are an integral part of the chromosome structure.
Within the eukaryotic cell, the chromosomes are surrounded by a double membrane, the nuclear envelope, but in eukaryotic cells the genetic information is contained within a region called the nucleoid.
Three differences between plant and animal cells:
Plant cells contain a tough, slightly elastic cellulose cell wall in addition to the cell membrane, but this cell wall is a non-living part of the cell. Also, plant cells contain chloroplasts for photosynthesis, animal cells do not.
Animal cells contain centrioles which are involved in cell reproduction, plant cells do not.
Pits and plasmodesmata are found in the cell wall of plant cells, and plant cells also contain a much larger, centralized vacuole.
The Endosymbotics Theory: The endosymbiotic theory assumes that eukaryotes evolved from prokaryotes, because a prokaryotic cell acquired organelles. It states that it is possible that a heterotrophic prokaryote (one which obtains energy and organic matter from inorganic raw materials and an external energy source) which, instead of being digested, became a symbiont (lived in association with) inside the heterotroph, enabling it to carry out photosynthesis. Equipped with its own DNA, the symbiont may be divided inside the host cell very time the host cell itself divided, and in this way the symbiont may have become a chloroplast inside the host cell. Evidence: - Ribosomes in mitochondria and chloroplasts are the same sizes as those found in modern prokaryotes and significantly smaller than those found in the cytosol of a eukaryote. - The inner membranes of mitochondria and chloroplasts have several enzymes and transport systems which resemble those found in the cell membranes of modern prokaryotes. - Mitochondria and chloroplasts have their own DNA in the form of a ring, just as in prokaryotes found today.
Eukaryotic cells have membrane-bound organelles and perform functions in a similar way to organs in an organism.
RER (Rough endoplasmic reticulum)- to isolate and transport proteins which have been synthesised by the ribosomes to other cells. Ribosomes- synthesise proteins
Smooth endoplasmic reticulum- synthesis and transport of lipids and steroids.
Golgi apparatus- assembly point through which raw materials for secretion are funnelled, carbohydrate components are added, and then are shed from the cell.
Lysosomes- destroy unwanted structures (e.g. old mitochondria), or entire cells by the rupturing of the lysosome membrane and the releasing of digestive enzymes (e.g. tadpole tails in frog metamorphosis).
Mitochondria- concerned with the chemical reactions of aerobic respiration; i.e. energy is converted to ATP here (the inner surface is infolded to increase surface area).
Nucleus- contains genetic information (bounded by a nuclear membrane).
Chloroplasts- contain chlorophyll used in photosynthesis
DNA in Prokaryotes Vs. DNA in Eukaryotes:
DNA is loose in prokaryotic cells, in eukaryotic cells the DNA is contained within a nuclear envelope.
DNA in prokaryotic cells is circular, in eukaryotic cells it is arranged in chromosomes
Prokaryotic cells have about 1/1000 as much genetic material.
Cell Reproduction:
prophase
separate when nuclear membrane disappears
nucleolus disappears
centrioles go to poles
spindle fibers appear
chromosomes get shorter and thicker
metaphase
centrioles become asters
the chromosomes line up “single file” at the equator
spindle fibers attach to centromere with kinetochore
anaphase
the chromatids are pulled towards opposite poles
telophase
the nuclear membranes reappear
nucleolus reappears
asters become centrioles
in animals spindle fiber disappears
chromatids get longer and thinner and become chromatin.