biology exam I
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- The formation of Earth
- 4.5 billion years ago
- Origin of life on earth
- 3.75 billion years ago
- First invertebrates + Cambrian Explosion of Life
- 600 million years ago
- First fish
- 500 million years ago
- First land plants and animals
- 400 million years ago
- Permian Extinction
- 250 million years ago
- Dinosaurs
-
230 million years ago
- First mammals
- 200 million years ago
- First Hominoids
- 500,000 years ago
- First modern humans
- 70-200,000 years ago
- spontaneous generation
- The theory that life just sort of appeared from various objects; such as frogs sprouting from wet soil.
- Francesco Redi
- 1668, tested and disproved the theory of spontaneous generation with meat in jars + flies
- vitalism
- Life processes determined by laws of physical universe in combination with a vital force. (i.e. the soul)
- Early Earth atmosphere
- Hydrogen (H2), Methane (CH4), Ammonia (NH4), Water, Nitrogen (N2), small amounts of carbon dioxide/monoxide, and hydrogen sulfide
- Today's atmosphere
-
Nitrogen (N2), Oxygen (O2), carbon dioxide (CO2), water (H2O)
- organic
- Referrs to compounds that contain carbon
- Stanley Miller and Harold Urey
- University of Chicago, 1953 - recreated the primordial atmosphere and used electricity to successfully spark inorganic compounds to create organic compounds.
- biology
- the study and structure of organisms
- organisms
- all living things
- homeostasis
- a natural balance that is maintained for optimal function
- the scientific method
- question > research > hypothesis > procedure/method > data > observations > conclusion
- hypothesis
- Not a question, but a preliminary explanation for a question; an educated prediction or guess.
- theory
- A well accepted conclusion with support from MULTIPLE experiments and multiple sources.
- Chemistry
- the study of the composition, properties, and behavior of natural substances. The scientific study of matter.
- orbitals
- The circular paths that electrons go in to orbit the nucleus
- valence electrons
- Electrons that occupy the outermost orbital
- ion
- Electrically charged atom; proton and electron numbers are not equal
- Atomic number
- Number of protons in an atom
- nuclear reactions
- When the number of protons in an atom change
- isotope
- Different number of neutrons in a particular atom.
- compound
- A substance made of more than one element; combined with the power of a bond.
- bond
- sharing valence electrons in the outer orbital.
- covalent bond
- Sharing of electrons; creates molecules
- ionic bond
- Transfer of electrons; not an equal sharing of electrons. Stronger than covalent bonds, but easier to break. One side has a charge, and the other doesn't.
- energy
- the ability to do work
- chemical reaction
- an energetic process of chemical change. all reactions have reactants and products.
- reactants and products
- starting materials and ending materials of chemical reactions
- enzymes
- biological catalysts to help reactions go faster and more efficiently.
- Unique properties of water
-
1. Cohesion
2. Adhesion
3. Capillarity
4. High surface tension
5. Solid form is less dense than liquid
6. High specific heat - Hydrogen bond
- Electrons are not shared; ie in water. creates a polar molecule
- polar molecule
- molecule with a negative and positive pole, partially charged; not an ion
- Carbon
- the fundamental building block of biological molecules; four valence electrons; can create up to four different bonds per atom!
- Hydrocarbon
- a purely hydrogen and carbon molecule; nonpolar and hydrophobic.
- macromolecules
- Carbon-rich molecules in the foods we eat
- Functional groups of organic macromolecules
- Lipids, Carbohydrates, Proteins, and Nucleic Acids. composed of nitrogen, phosphorus, sulfur, carbon, oxygen, and hydrogen.
- metabolism
- how the body is able to process and use energy input
- polymers
- What most all food is made up of. Chemical units made up of many monomers and dimers.
- hydrolysis reactions
- water molecule slices a larger molecule; gain water in the process; is how digestive processes break down polymers into monomers.
- condensation reactions
- process of monomers being recombined into polymers; lose water in the process.
- Proteins
- Polar, made of amino acids and polypeptides.
- polypeptides
- Polymer forms of proteins.
- amino acids
- Monomer units of proteins that make up polymer polypeptides. Two amino acids bonded together are usually messengers called hormones.
- Carbohydrates
- Polar, made of polymers called polysaccharides and monomer monosaccharides.
- polysaccharides
- polymer carbohydrates; a type of sugar. digested very slowly over time to give a long, steady stream of energy.
- monosaccharides
- monomer carbohydrates; easier to digest
- Lipids
- Fats, oils, waxes. Nonpolar and repel water. Do not have true monomer units - they are long hydrophobic chains; can be saturated or unsaturated with hydrogen atoms.
- Nucleic Acids
- Stuff our DNA is made of.
- nucleotides
- monomer units of nucleic acids. Composed of a pentose sugar, phosphate group, and a nitrogenous base
- pentose sugar
- 5 carbon sugar
- nitrogenous base
- A functional group with nitrogen; with four basic bases: A T C G
- Cells
- basic structural unit of organisms
- The cell theory
-
1858.
1. All organisms consist of one or more cells.
2. The cell is the basic unit of structure
3. All cells arise only from preexisting cells - Invention of the microscope
- Von Leeuwenhoek; end of the 17th century. 4x zoom and very distorted; eventually refined to have 300x magnification.
- Micrographia image
- 1665, Robert Hooke; after looking at thinly sliced cork under a microscope. He described what he saw as "cells" and the word stuck despite cork actually being the cell walls of dead plant tissue.
- Light microscope
- Uses light to look at thinly sliced, stained specimens so that light passes through them. 1500x magnification.
- electron microscope
- 1930s. Two types - Transmission Electron Microscope and Scanning Electron Microscope
- TEM
- Transmission Electron Microscope
- SEM
- Scanning Electron Microscope, 1950s
- Basic components of cells
-
1. Cell membrane
2. Cytoplasm (goo inside the cell)
3. DNA - Prokaryotic cells
- Simpler, smaller cells without nuclei or membrane-bound organelles. DNA floats freeform in the cytoplasm as well as ribosomes.
- Eukaryotic cells
- Larger cells that contain membrane-bound structures called organelles, like little organs.
- Animal cell
- A eukaryotic cell, with mitochondrion, cytoplasm, plasma membrane, endoplasmic reticulum (rough and smooth), ribosomes, golgi complex, nucleus, lysosome, cytoskeleton.
- Mitochondrion
- Kidney shaped organelles that have a double membrane; they generate energy for the cell and perform lots of metabolic reactions
- Cytoplasm
- The jell-o like goop that fills in the cell and holds everything together
- Plasma membrane
- Holds the cell in shape, selectively permeable (can select what is able to enter and exit the cell)
- Endoplasmic reticulum (ER)
- "inside plasma", a reticulated surface. Two types - rough and smooth. Rough ER has ribosomes embedded in the surface, responsible for packaging newly synthesized proteins. Smooth ER synthesizes and packages lipids.
- Ribosomes
- little balls floating through the cytoplasm.
- Golgi complex
- "Post office" of the cell. Recieves various vesicles that contain substances secreted by other organelles. Sorts, modifies, repackages the substances and prepares them for cell exit.
- Nucleus
- Central region of the cell, containing the DNA and RNA
- nuclear envelope
- Double membrane that protects the nucleus
- nuclear pores
- Holes in the nuclear envelope used for exchange between the nucleus and the cytoplasm
- chromatin
- DNA in uncondensed form in the nucleus
- nucleolus
- The "nucleus" of the nucleous - the wad of self attracting chromatin
- Lysosome
- Digestive organ, containing hydrolytic enzymes, breaks down food and digests it.
- vacuole
- A way to transport large molecules into the cell; the cell membrane folds around the molecule and pinches it off to make a little transport bubble for it.
- cytoskeleton
- Holds cell shape together, the backbone of the cell: made of microtubules and microfilaments.
- microtubules
- Used for various purposes, such as creation of centrioles (for mitosis), and projections on the outside of the cell like scilia or flagella.
- microfilaments
- Long intertwined chains that form the bulk of the "skeleton" of the cell.
- Plant cell
- A eukaryotic cell, very much like an animal cell, but with chloroplast, central vacuole, cell wall, and plasodesmata
- Chloroplast
- Contain chlorophyll; used for photosynthesis, can also store sugars and starches.
- Central vacuole
- Filled with water and nutrients for the cell; partly provides rigidity of the plants, when the plant needs a lot of water it uses this and it causes the cells to deflate and "wilt"
- Cell wall
- Has a cell membrane, but the next layer is a rigid wall; lots of nutrition for animals that ingest it, including fiber called cellulose.
- Plasmodesmata
- pores inside cell walls
- composition of cell membrane
- Phospholipid. Lipid makes the hydrophobic tail on the inside, and the phosphorous head is the hydrophilic head on the outside. Structure helps it maintain homeostasis.
- aquaporins
- Special channels in the cell membrane that allow water to flow in rapidly.
- Passive transport
-
1. Does not require energy from cell
2. From areas of high to low concentration (concentration gradient)
3. Simple diffusion is most basic type
4. Osmosis
5. Facilitated diffusion - osmosis
- water-specific simple diffusion
- facilitated diffusion
- diffusion in which special transport proteins are required in the cell membrane, like special tunnels
- Cell active transport
-
1. requires energy from cell
2. against concentration gradient; low to high
3. Typically uses ATP
4. Special protein pumps - ATP
- adenosine triphosphate, used in active transport
- cell membrane pumps
- Used in active transport; do not activate without ATP input. They break a phosphorus molecule off of ATP to turn it into ADP and generate energy for the pump.
- Bulk flow
- Uses vesicles for endocytosis (entering) or exocytosis (exiting). For extremely large molecules.
- catabolism
- digestion of large molecules into simpler subunits.
- anabolism
- building up of larger molecules from smaller ones.
- Enzyme traits
-
1. Biological catalysts
2. Substrate specific (particular to one type of substance)
3. Active site, similar to a lock and key