Biology Midterm Study Guide—Chapters 1,3,4,5,6Prologue:Biology is the study of life.Plants, animals, fungi, protists & bacteria are examples of living organisms.Biotic= a living organism, Abiotic= not livingSteps of the Scientific Method1. Problem2. Hypothesis3. Design an Experiment4. Run/Conduct5. ConclusionWhat is a Variable?- The part of an experiment that changes.What is a Control Group?- The part of an experiment that doesn’t change.o A control group is necessary for an experiment because we need to know what factor that is not going to change, so we can see what different things happen to the variables.What is a Hypothesis?- An educated guess that has not been proven.- An answer to a scientific problem, the explanation for an observation.What is a Theory?- A hypothesis that has been proven.What is a Law?- A bunch of theories put together.Chapter 1:Protons are positive, neutrons are neutral, electrons are negative.What is an element?- A substance composed of atoms that are chemically identical, alike in their # of protons, and cannot be broken down into a simpler substance.6 Most Common Elements:1. Carbon2. Hydrogen3. Nitrogen4. Oxygen5. Phosphorus6. SulfurWhat is a molecule?- The smallest unit of a compound, composed of atoms covalently bonded to one another.When atoms are joined, a bond forms. Energy is stored in a bond, so when a bond breaks, either free energy or heat energy is released.- Atoms make bonds because they want to fill the empty spaces on their electron shell.How many bonds do they like to make? (HONC= 1234)What is a chemical reaction?- When 2 or more atoms/molecules come together and interact w/each other.Isotope= atom with a different number of neutronsCovalent Bonds are not charged, they share electrons.a) Polari. When they share the electrons, one atom is closer to it then another. b) Non-polari. When they share the electrons equally 50/50.Ionic Bonds are charged because they steal electrons from other atoms.Cohesion: when water molecules bond with other water moleculesAdhesion: when a water molecule bonds with another molecule (not water)What is pH ?- The measure of H+ ions.o On a scale from 0-14, 7 would be neutral, 0-6 would be acids & 8-14 would be bases. The acids have a high concentration of H+, low OH. The bases have a low concentration of H+, high OH.Organic= compounds that are made up of carbon atoms.Ex) hydrogen, oxygen, nitrogen, carbon**Proteins, like enzymes & transport proteins, are made out of amino acids. They help to fight against disease and helps to speed up chemical reactions in enzymes. Primary: determines the sequence, bond to form a strand of alpha helix Secondary: as they start folding up, beta pleated sheets are made Tertiary: hydrophobic part of the protein curls in the inside, forming a ball Quaternary: when several folded balls of protein, form to make a bigger ballLipids, like waxes & sterols, are made of glycerol and fatty acids. They provide long term energy storage and protects vital organs.Carbohydrates, like starch, cellulose & glucose, are made of monosaccharides. They provide short term energy storage and help with plant structure.Nucleic Acids, like RNA and DNA, are made of nucleotides. They store genetic information and gives instructions on how to build proteins. They’re made up of a phosphate, sugar & base.(double stranded) DNA: adenine, guanine, cytosine, thymine(single stranded) RNA: adenine, guanine, cytosine, uracilChapter 3:What is the purpose of the cell membrane ?- To enclose the organelles and cytoplasm in the cell.- To protect the cell, filters what goes in and out.Parts of the cell membrane:a) Phospholipids- act as a barrier for the cell, hydrophilic heads, hydrophobic tailsb) Proteins- act as a doorway for the bigger molecules to pass throughc) Carbohydrates- have glycans attached to send messages & communicate w/other cellsd) Cholesterol- slows down the movement of phospholipidsWhat molecules can pass easily though the membrane? Small polar and non-polar moleculesWhat molecules need help from transport proteins? Larger uncharged molecules and ions.Passive Transport: requires no energy because it moves from a high to low concentration.a) Diffusion- when the molecules move through the phospholipids easilyb) Facilitated diffusion- when molecules need help, so move through the transport proteinActive Transport: requires energy because it moves from a low to high concentration gradient.a) Transport protein- take the molecules and pushes it from low to highb) Endo/exocytosis- moves from low to high with the help of vesiclesHow does surface area affect diffusion?- The larger the surface area, the higher the diffusion rate because there is more space/ surface area in which to diffuse in.Hypotonic- the low concentration the solution is inHypertonic- the high concentration the solution is inIsotonic- equilibrium where the solution is inOsmosis is when water moves from a low to high concentrated solution through a membrane.Turgor- a cell’s swelling against its cell wall caused by the pressure of the cell’s contents.Chapter 6:Scientists that contributed to cell theory: Robert Hooke discovered cells by looking at cork. Robert Brown discovered the nucleus of the cell. Theodor Schwann found out that animals were made out of cells too. Anton van Leeuwenhoek discovered protists by looking at water.What is a cell?- The basic living unit of structure and function, cannot be broken down.Cell theory states that:1) All living things are made of cells.2) Cells are the basic unit of structure and function.3) All cells come from pre-existing cells.Advantage DisadvantageLight Microscope You can see the living organisms inside without killing the sample.They have to be large organisms.Electron Microscope You can see very small organisms that are in the cell.It kills the sample because it uses a lot of power.Prokaryotes don’t have organelles, are unicellular, no nucleus, and simple. Ex) bacteriaEukaryotes have organelles, are multicellular, have a nucleus and are more complex. Ex) plantsWhat is a colony?- A group of unicellular microorganisms living together. All the cells are similar, they movetogether, are coordinates and each cell has a specialized roles. Ex) Volvex- Disadvantages are that they can’t grow to be very large and only some can reproduce.Multicellular organisms contain organ systems, are large & more complex then single celled organisms. They have systems so most cells
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