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EOCT Review Questions

Introduction

  1. What is the ultimate goal of science? Developing an understanding of the natural universe which is free of human bias.
  1. How are universal principals discovered in science? Obervations, Research – design and do experiments
  1. What are possible sources of bias in research? Instrument error – ex. not calibrated correctly, measurement error, researcher error
  1. What is the fastest way to get new research out to the research community? The World Wide Web! (Must be careful with the data!) Journal publications are also important because many require a peer review.
  1. What are some examples of how theories have changed and why? World is flat, center of universe; spontaneous generation, etc. These change due to better technology, a new understanding of what the data represents, etc.
  1. Why do scientific problems rely on the “design and execution” of new experiments? It may reinforce or weaken opposing explanations.
  1. What is anthropomorphism and how can it affect research? Attribution of human motivation, characteristics, or behavior to inanimate objects, animals, or natural phenomena. It assumes that everything “works” the way we do… adds tremendous bias to research!
  1. Know lab safety!!!!!

Part I

  1. What does the term biology mean? The study of life.
  1. What are the steps to the scientific method in order? 1: Make observations and ask questions. (Define the problem.) 2: Gather background information. (Research, this is where you educate yourself to make the “educated guess”! 3: Develop a hypothesis 4: Test the hypothesis (experiment, collect data, and analyze data) 5: Draw conclusions and identify new questions 6: Communicate the results: Publish findings – subject to peer review
  1. What is the difference between independent and dependent variables? The independent variable is what the experimenter is manipulating. What the independent variable affects is called the dependent variable. Ex. Fertilizer would be the independent variable and the rate of plant growth would be the dependent variable.
  1. What is the main tool of the biologist? Microscope
  1. What do the following branches of biology study?

Botany – plants

Ecology – the interactions of organisms with their environments

Genetics – heredity

Microbiology – microorganisms

Taxonomy – classification

Zoology – animals

Part II

  1. What are the three main ideas of the cell theory? 1) All cells come from pre-existing cells 2) The cell is the basic unit of structure and function 3) All living things are composed of one or more cells.
  1. What are the characteristics of life? 1) composed of cells 2) reproduce using a universal genetic code 3) growth and development 4) obtain and use materials and energy 5) (uses energy to) maintain homeostasis (stable internal environment) 6) as a group, change over time 7) respond to stimuli
  1. What is homeostasis and how is it important for living organisms? Maintaining internal balance or equilibrium. Organisms must respond and adjust to environmental stressors such as temperature, sunlight, chemicals and other organisms. Cells must regulate water, glucose, nutrients and wastes. The membrane it essential in maintaining a cellular homeostasis.
  1. How do eukaryotes differ from prokaryotes? Eukaryotes have a nucleus and other membrane bound organelles and prokaryotes do not have a nucleus and other membrane bound organelles. (Both have DNA, cell membrane, cytoplasm and ribosomes) Additionally, eukaryotic cells can assemble into multicellular organisms.
  1. Describe the fluid mosaic model of the cell membrane. The model used to describe the cell membrane as a fluid bi-layer of phospholipids with proteins embedded through out and cell makers on the outside.
  1. Explain how the cell membrane regulates cell behavior. The cell membrane is selectively permeable regulating what enters and exits the cell. (Maintaining homeostasis!) The membrane has different chemical receptors embedded on its surface allowing certain chemicals to target it while allowing other cells to ignore the chemicals. Ex. Nerve cells: chemical in the bloodstream causes the nerve cell to respond to a stimulus and leaves other cell unaffected. Hormones work this way as well!
  1. Fill in the following chart of cell organelles:

Organelle /

Function

/ Prokaryotes or Eukaryotes? / Animal cells or Plant cells?
Nucleus / Control center of the cell. Contains the DNA. / Eukaryotes / Both
Nuclear envelope / Regulates what enters and exits the nucleus. Has nuclear pores. / Eukaryotes / Both
Ribosomes / Function in translation of protein synthesis (makes polypeptide chains which become proteins!) / Both / Both
Mitochondria / Carries out cellular respiration. Generates energy (ATP) from glucose / Eukaryotes / Both
Chloroplast / Captures solar energy and makes glucose during photosynthesis using the pigment chlorophyll / Eukaryotes / Plant
Endoplasmic Reticulum / Membraneous channels which transport materials within and out of the cell / Eukaryotes / Both
Golgi Apparatus / Modifies, packs and ships materials (proteins and lipids) out of the cell by pieces pinching off (vesicles) and fusing with the cell membrane. / Eukaryotes / Both
Cell membrane (a.k.a. Plasma membrane) / A flexible, phospholipid bi-layer embedded with proteins which regulates what enters and exits the cell. / Both / Both
Cell Wall / Rigid structure which provides additional support and protection for some cells. / Both / Plant, Bacteria, Fungi, and some Protista (never animals!)
Cytoplasm / Cellular mixture of water and dissolved substances and organelles found within the cell but not including the nucleus. / Both / Both
  1. How is active transport different form passive transport? Active transport requires the use of energy (going against the concentration gradient – uphill) to move materials across the cell membrane (endo- and exo- cytosis) and passive transport does not require energy (going with the concentration gradient – down hill) to move materials across the membrane (osmosis, diffusion, and facilitated diffusion). Ex. of active transport: Sodium potassium pump
  1. Explain/draw endocytosis and exocytosis. Endocytosis – the use of energy to move larger particles into the cell. 2 Types: phagocytosis – extensions of the cell membrane surround and pull in large particles, creating a vacuole (cell eating). pinocytosis – a pinching in of the cell membrane bringing smaller particles into a vesicle (cell drinking). Exocytosis is the opposite of endocytosis, it is the use of energy to remove larger particles from the cell.
  1. Define each of the following:

Diffusion – The movement of molecules from an area of higher concentration to an area of lower concentration. (Passive transport – going with the gradient)

Osmosis – The movement of water through a semi-permeable (or selectively permeable) membrane going from an area of higher concentration to an area of lower concentration. (Passive transport – going with the gradient)

Facilitated diffusion – The movement of molecules across the cell membrane through carrier molecules/protein channels. Ex. glucose Does not require energy – passive transport!

Isotonic – Solution on both sides of the cell have the same concentration of dissolved substances (solute). Water move into and out of the cell evenly – equilibrium is already established.

Hypertonic – Solution on the outside of the cell has more solute (dissolved substances) than inside the cell. Water will move out of the cell to establish equilibrium.

Hypotonic – Solution on the inside of the cell has more solute than outside the cell. Water will move into the cell to establish equilibrium.

Part III

  1. Why is water important in biology? WATER IS POLAR! Universal solvent, moderates climates (holds heat), cools through evaporation, freezes from the outside in, adhesive (attracted to other things – allows for capillary action, and cohesive (attracted to other water molecules).
  1. What is hydrogen bonding? How is it important in DNA? A weak bond formed from the attraction of a positive hydrogen on one molecule to a negative part of another molecule. Holds the base pairs of DNA together, also creates unique properties of water.
  1. What is the pH range of acids? Of bases? Acids: 0-6.9 ex. citric acid Bases: 7.1-14 ex. bleach *7 is neutral ex. water
  1. Differentiate between endergonic and exergonic reactions. Endergonic: More energy is put into the reaction than comes out of the reaction. The products have more energy stored in the bonds than the reactants. Ex. Photosynthesis. Exergonic: More energy comes out of the reaction that was put into the reaction. The products have less energy that the reactants. Ex. Cellular respiration
  1. Fill in the chart of 4 main organic compounds:

Organic compound / Monomer / How are they used? / Example:
Carbohydrate / monosaccharide (simple sugar)
ratio of atoms: 1C:2H:1O / quick energy / glucose, sucrose, starch, glycogen, cellulose (monosaccharides, oligosaccharides, and polysaccharides)
Lipid / glycerol and fatty acids
Made up of C, H, and O but less O than carbs. / cell membrane, energy storage, shock absorber, insulation (non polar – insoluble in water!) / fats, oils, waxes and steroids
*waxes are long fatty acid chains attached to an alcohol.
Protein / amino acids
*contains nitrogen
**polypeptide chains / build structure and support, immune system, and enzymes, O2 transport / antibodies, muscle, collagen, hemoglobin, insulin
Nucleic Acid / nucleotides (composed of a 5 C sugar, phosphate group, and a nitrogen base) / heredity and making proteins
*coenzymes / DNA and RNA
ATP, ADP, NAD+ and NADP+
  1. What are enzymes? How do they regulate the rate of reactions? STRUCTURE IS RELATED TO FUNCTION! Enzymes are proteins which function as a catalyst. They speed up the rate of reactions by reducing the amount of activation energy required to start the reaction but are not used up or permanently altered in the reaction. The substrate binds with the active site of the enzyme, the reaction occurs and the products are released. Enzymes work in both directions. *Enzymes are very specific for the substrate/reaction they facilitate. This is called the Lock and Key Model . Ex. lipase helps with the digestion of lipids. The concentration of the enzyme can determine the rate of the reaction. Ex. Dilute the enzyme and the reaction rate slows, add more enzyme and the reaction rate speeds up . Some serious genetic disorders are caused by faulty critical enzymes (the genetic code for the enzyme has an error). Ex. Tay Sachs Disease and PKU (phenylketoneuria).
  1. How can you tell from the name of a compound that it is an enzyme (usually)? A sugar? Name of enzymes tend to end with –ase, names of sugars tend to end with –ose.
  1. Explain the following three factors that affect enzymes: pH, temperature, and salinity. Give examples.

Enzymes tend to be specific for the pH they work in like trypsin and pepsin in digestion.

Most enzymes denature at high temp.: Fresh pineapple can not be used in Jello but canned pineapple can due to the fact that the canning process heated and denatured the enzymes that would otherwise stop the Jello from gelling. This is also why high temperatures are dangerous when you get sick! Cold temperatures do not denature the enzyme but slow down molecular activity. That is why we put things in the refrigerator. The cold slows down the chemical activity of the bacteria, etc. that want to break down our food, given time the food will still go bad!

Most enzymes will not work in a high salt concentration: this is why salt is often used as a preservative, stops/slows bacterial decomposition!

  1. What is it called when a protein unravels? Denature
  1. Fill in the following chart to compare photosynthesis and cellular respiration.

Process / Organelle where it occurs / What is needed? / What is produced? / Overall equation
Photosynthesis / chloroplasts / CO2, H2O, and sunlight (photons) / glucose and O2 / 6CO2 + 6H20 -> C6H1206 + 02
Cellular Respiration / mitochondria / glucose and O2 / CO2, H2O and energy (ATP) / C6H1206 + 02 -> 6CO2 + 6H20
  1. What is fermentation? Why and does it occur? The breakdown of glucose (sugar) to release energy (ATP) in the absence of oxygen. Occurs in the cytoplasm of a cell. In humans this occurs in the muscle cells producing lactic acid which causes cramps and soreness! In other organisms it produces alcohol. Very inefficient! Only produces a net total of 2 ATP’s!
  1. What are the stages of photosynthesis, where do they occur in the cell, and what is produced in each stage? The light reaction = “Photo” and the Calvin cycle = “synthesis”

Stage of photosynthesis /
Where it occurs
/ Produced
Light reaction
(Traps light) / thylakoid membrane / O2 (waste from breaking down water), ATP, NADPH
Calvin Cycle
(Fixes carbon) / Stroma / Simple sugars, PGAL
  1. What are the stages of cellular respiration, where do they occur in the cell, and what is produced in each stage? Food is the source of heterotrophs energy. The digestive system (we have an entire system designed to get us energy!) breaks down food and blood brings glucose to the cells where it diffuses into the cells with the help of insulin (facilitated diffusion).

Stage of cellular respiration / Where it occurs / Produced
Glycolysis / cytoplasm / pyruvic acid, 4 ATP but used 2
Acetyl CoA production / inner space of mitochondria membrane / Acetyl Co A, 2 CO2
Krebs Cycle / Matrix / 4 CO2, NADH, FADH, 2 ATP
Electron Transport Chain and chemiosmotic phosporylation / Cristae / 32 ATP; NAD+ and FAD+ (to be recycled in the Krebs cycle)

*the CO2 is a waste product, oxygen is the ultimate electron acceptor at the end of the electron transport chain and becomes a part of water.

  1. What is ATP? What is it used for? Adensosine Triphosphate. ATP and ADP are nucleotides! Unstable, high energy molecule used to do cell work.
  1. What happens when a phosphate is removed from ATP? What happens to the ADP? Energy is transferred from one molecule (energy intermediate molecules) to another (*phosporylation). Like playing hot potato! The ADP goes back a cycle to get recycled by having a P added back on to make it ATP! ATP ↔ ADP + P + E


*bioluminescence – the production of light through a series of chemical reaction by a living organism. Ex. lightning bugs, many deep-sea organisms. The reactions are powered by ATP!

  1. In a chemical equation, where are the reactants? (left or right side?) where are the products? The reactants are on the left side of the equation and the products are on the right side of the equation. Ex. C6H1206 + 02 -> 6CO2 + 6H20

reactants products

Part IV

  1. List the steps of the cell cycle (NOT the steps of mitosis). G1 phase: cell growth, S phase: DNA replication, G2 phase: growth and preparation for cell division, Mitosis: PMAT, and Cytokinesis: division of the cytoplasm
  1. What happens during Interphase? The cell grows, adds organelles. May also undergo preparation for cell division (includes G1, S, and G2 phases)
  1. What happens during mitosis? The nucleus divides. Keeps the number of choromosomes constant from one cell generation to the next. Purpose: Allows eukaryotes to grow and repair tissues. Ex. Skin grafting: burn victims can have a small piece of healthy skin removed and cultured. The new skin is used to cover the burned areas. Mitosis is also used for asexual reproduction such as budding, binary fission, regeneration, etc.
  1. What happens during cytokinesis? The cytoplasm divides. In animal cells, the cell membrane pinches inwards. In plant cells, a cell plate forms which will become the new cell wall.
  1. What are the 4 main stages of mitosis (in order)? Prophase, Metaphase, Anaphase, and Telophase Purpose: to make an exact copy of the cell!
  1. Describe what is happening in the stages of mitosis:

Stage / Description
Prophase / DNA coils into chromosomes and are visible, spindle fibers from and radiate across the cell, and the nuclear membrane starts to break up
Metaphase / The duplicated chromosomes line up randomly in the center of the cell between the spindles at the equator.
Anaphase / The duplicated chromosomes are pulled to opposite ends of the cell. Every chromosome that was present in the parent cell is now represented by the daughter chromosome at the poles.
Telophase / The nuclear membrane forms around the chromosomes at each end of the cell. The spindle fibers disappear and the chromosomes disperse and become less distinct.
  1. What is the purpose of meiosis? The purpose is to produce gametes with ½ the number of chromosomes (haploid - n) compared to the parent cell (diploid - 2n). Additionally, the chromosomes have been modified through crossing-over and are genetically different (genetic recombination) from the parents’.
  1. Define haploid and diploid. What is the human haploid and diploid number? Haploid (n) – ½ the # of chromosomes, cell only contains one set. Diploid (2n) cell contains both sets (maternal and paternal) of chromosomes. Humans: haploid = 23; diploid = 46
  1. Compare sexual reproduction and asexual reproduction. Sexual: offspring are genetically different that the parents, requires 2 parents/fusion of gametes. Asexual: offspring are “clones”, genetically identical to the parent cell.
  1. Fill in the chart to compare mitosis and meiosis.

Starts with / Ends with / # of stages / Somatic cells or sex cells?
Mitosis / 1 diploid cell / 2 diploid (2n) cells / 1 phase: 4 stages / somatic
Meiosis / 1 diploid cell / 4 haploid (n) cells / 2 phases: meiosis I and meiosis II – 8 stages / sex cells = egg and sperm (gametes)
  1. What is a gamete? Is it haploid or diploid? How are sperm and egg formation different? A gamete is a sex cell, either an egg or a sperm. Gametes are haploid. Spermatogenesis: the formation of sperm through meiosis results in 4 sperm cells. Oogenesis: the formation of an egg through meiosis results in 1 egg cell (ova) and 3 polar bodies. The difference is due to unequal division of the cytoplasm.
  1. Who is Gregor Mendel? Austrian Monk who predicted how traits are carried from one generation to the next. Father of Classical Genetics.
  1. What organism did Mendel study?