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Chapter One
Chapter Two
Chapter 3
Chapter 4
Chapter 5
100
What is an emergent property, and why is life considered an emergent property?
An emergent property is a characteristic of a system that does not appear in any of a system's component parts. Life is considered an emergent property because there are 7 components necessary to be considered a living thing. Considered separately, each component in itself is not alive.
100
How do saturated and unsaturated fats differ in chemical structure and physical properties?
The fatty acid tails of saturated fats have only single bonds, while the fatty acid tails of unsaturated fates have one or more double bonds tat kink their carbon chains. Saturated fats tend to remain solid at room temperature, while unsaturated fats are liquid at room temperature.
100
What is the difference between rough endoplasmic reticulum and smooth endoplasmic reticulum?
Rough Endoplasmic Reticulum is studded with ribosomes (for protein production); smooth endoplasmic reticulum has no ribosomes.
100
What is an active transport and a passive transport?
Active transport - energy requiring mechanism by which a transport protein pumps a solute across a cell membrane against its concentration gradient. Passive transport - mechanism by which a concentration gradient drives the movement of a solute across a cell membrane through a transport protein. Requires no energy input. *Active requires energy; passive requires no energy input
100
What is the difference between heterotrophs and autotrophs? Give an example of each.
Heterotrophs get energy and carbon by breaking down organic molecules assembled by other organisms (i.e. animals). Autotrophs harvest energy directly from the environment, and they get carbon from inorganic molecules (i.e. plants).
200
What is scientific theory?
A scientific theory is a hypothesis that as not been disproven after many years of rigorous testing and is useful for making predictions about other phenomena.
200
What can you learn from the number of electrons in the outer shell of an atom?
If an atom's outermost shell is full of electrons, we say it has no vacancies (such as Helium). Atoms of such elements are chemically inactive, which means they are most stable as single atoms. If an atom's outermost shell has room for another electron, it has a vacancy. Atoms with vacancies tend to interact with other atoms, making it less stable.
200
Explain the cell theory. (Hint: It consists of 4 generalizations.)
1. All organisms consist of one or more cells. 2. The cell is the smallest unit of life. 3. Each new cell arises from another cell. 4. A cell passes hereditary material to its offspring.
200
What is a metabolic pathway? What 3 mechanisms control enzyme mediated reactions?
Metabolism refers to the enzyme-mediated chemical reactions by which cells acquire and use energy as they build and break down organic molecules. Any series of enzyme-mediated reactions by which a cell builds, rearranges, or breaks down an organic substance is called a metabolic pathway. Control mechanisms enhance or inhibit the activity of many enzymes. The adjustments help cells produce only what they require in any given interval. The 3 mechanisms that control enzyme mediated reactions are: feedback inhibition, allosteric sites, and electron transfer chains.
200
What are the three stages in which aerobic respiration occurs?
1. Glycolysis - a set of reactions in which glucose or another sugar is broken down to two pyruvate for a net yield of two ATP 2. Acetyl - CoA formation and the Krebs cycle - Cyclic pathway that, along with acetyl-CoA formation, breaks down two pyruvate to carbon dioxide for a net yield of two ATP and many reduced coenzymes. 3. Electron transfer phosphorylation - Metabolic pathway in which electron flow through electron transfer chains sets up a hydrogen ion gradient that drives ATP formation.
300
What is the purpose and benefit of an experiment?
The purpose of an experiment is to support or falsify a prediction. The benefit of experiments is that they help researchers unravel causes of complex natural processes by focusing on the effects of changing a single variable.
300
What is the difference between an atom, and element, and an ion?
Atoms are tiny particles that are building blocks of all substances; elements are pure substances, each consisting only of atoms that have the same number of protons in their nucleus; and an ion is an atom that carries a charge because it has an unequal number of protons and electrons.
300
What are the structure and function of mitochondria and chloroplasts?
Structure: Mitochondria - double membraned organelle. One membrane is highly folded inside the other. They have their own DNA and ribosomes. Chloroplasts - organelle formed by two outer membranes enclosing a semi-fluid interior called stroma. Function: Mitochondria - Produce ATP Chloroplasts - Specialize in photosynthesis
300
What is the advantage of using an electron transfer chain for metabolizing glucose (sugar) in cells, rather than actually “burning” sugar in the presence of oxygen?
Burning an organic substance in the presence of oxygen releases its energy all at once, explosively. An electron transfer chain releases the energy of electrons in small, usable increments.
300
How do photosynthetic organisms absorb light?
Energy radiating from the sun travels through space in waves and is organized as packets called photons. The spectrum of radiant energy from the sun includes visible light. Humans perceive different wavelengths of visible light as different colors. the shorter the wavelength, the greater the energy. Pigments absorb light at specific wavelengths. Photosynthetic species use pigments such as chlorophyll a to harvest the energy of light for photosynthesis.
400
There are multiple approaches to scientific inquiry. What are the 7 common steps/methods of any scientific study (a.k.a. scientific inquiry)?
1. Make an observation about some aspect of nature. 2. Frame a question about your observation. 3. Propose a hypothesis (testable explanation). 4. Make a prediction (a statement, based on the hypothesis, about a condition that should exist if the hypothesis is not wrong). 5. Experiment (test the accuracy of the prediction using real or model sytems). 6. Assess the results of the tests or observations (data) to prove or disprove the prediction. 7. Report all the steps of your work, along with conclusions, to the scientific community.
400
What are the different types of chemical bonds? Explain each one and tell its relative strength.
A chemical bond forms when the electrons of two atoms interact. Depending on the atoms, the bond may be ionic or covalent. An ionic bond is a strong mutual attraction of two oppositely charged ions (i.e. table salt). It is a strong bond. A covalent bond is a chemical bond in which two atoms share a pair of electrons. There are two types of covalent bonds: nonpolar (atoms participating in the bond share electrons equally) and polar (electrons are not shared equally). Covalent bonds can be stronger than ionic bonds, but they are not always so. A hydrogen bond is a weak attraction between a hydrogen atom and another atom taking part in a separate polar covalent bond. Hydrogen bonds form and break much more easily than covalent or ionic bonds do.
400
How do cells transfer materials and information to other cells, and what is the main difference between plant and animal cells?
Cells transfer materials and information to other cells via cell junctions. The main difference between plant and animal cells is that plant cells have a porous wall around the plasma membrane, while animal cells do not have walls.
400
What are the roles of ATP and ADP in metabolism? What happens when ATP releases energy?Which compound has the higher energy?
ATP (adenosine triphosphate) is the main energy carrier in cells. It accepts energy released by energy-releasing reactions, and delivers energy to energy-requiring reactions. Cells constantly use up ATP to drive energy-requiring reactions, so they constantly replenish it. When ATP loses a phosphate, ADP (adenosine diphosphate) forms. ATP forms again when ADP binds phosphate. ATP has the higher energy because it is a nucleotide with three phosphate groups. The bonds that link those phosphate groups hold a lot of energy. When ATP loses one phosphate group, the nucleotide is ADP.
400
What is the difference between light-dependent reactions and light-independent reactions, and where do they occur?
Light-dependent reactions convert light energy to chemical bond energy in the form of ATP. Oxygen is released and electrons end up in NADPH. Light-independent reactions use ATP and NADPH to assemble water and oxygen. These power the energy-requiring second stage of photosynthesis, which occurs in the stroma of chloroplasts. The light-independent reactions that make up this stage convert carbon dioxide to glucose and other carbohydrates. In chloroplasts, the light-dependent reactions of photosynthesis occur at a much-folded thylakoid membrane. The membrane forms a continous compartment in the chloroplast's stroma, where the light-independent reactions occur.
500
Name the 7 properties that all living things have in common (these define what it means to be living).
Living things: 1. Are composed of 1 or more cells, 2. Require energy and nutrients, 3. Maintain stable internal conditions (homeostasis), 4. Sense and respond to environmental stimuli, 5. Grow, 6. Reproduce, and 7. Have the capacity to evolve
500
What are the four basic classes of organic molecules? How do they differ structurally? Functionally?
The four basic classes of organic molecules are: carbohydrates, lipids, proteins, and nucleic acids. 1. Carbohydrates consist of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio. Cells use carbohydrates as structural materials for energy. 2.Lipids are fatty, oily, or waxy compounds. (a.) Triglycerides - lipids that serve as energy reservoirs in vertebrate animals (b.) Phospholipids - the main lipid component of cell membranes (c.) Waxes - lipid components of water-repelling and lubricating secrections (d.) Steroids - lipids that occur in cell membranes 3. Proteins are organic compounds composed of one or more chains of amino acids. These are the most diverse of all biological molecules. They move substances, help cells communicate, and defend the body. 4. Nucleic Acids are chains of nucleotides (small organic molecules, various kinds of which function as energy carriers, enzyme helpers, chemical messengers, and subunits of DNA and RNA) joined by sugar-phosphate bonds. Different RNAs interact with DNA and with one another to carry out protein synthesis.
500
What are the different types of membrane proteins and what are their basic functions? (Hint: There are 5 of them.)
1. Enzymes - accelerate chemical processes without being changed by them. 2. Adhesion proteins - helps cells stick together in tissues. 3. Recognition Proteins - tag a cell as belonging to self (to one's own body). 4. Receptor Proteins - Bind to a particular substance outside of the cell. 5. Transport Proteins - Passively or actively assist specific ions or molecules across a membrane.
500
What is meant by hypertonic, hypotonic, and isotonic? What is the impact of tonicity on cells?
Hypertonic (hyper = over) - describes a fluid with a higher solute concentration than another fluid Hypotonic (hypo = under) - the fluid with the lower solute concentration Isotonic - fluids that have the same solute concentration Cell membranes are selectively permeable, and water crosses them freely. Thus, if a cell's cytoplasm is hypertonic (over) with respect to the fluid outside of its plasma membrane, water will diffuse into it. It its cytoplasm is hypotonic (under) with respect to the fluid on the outside, water will diffuse out of it. Cells can maintain their cytoplasm at a constant volume by pumping water one way or the other across their plasma membrane.
500
Explain fermentation and lactate fermentation.
Fermentation is an anaerobic pathway by which cells arvest energy from carbohydrates. ATP can form in fermentation pathways, which are anaerobic (meaning, they do not require oxygen). Fermentation reactions regenerate the coenzyme NAD+, without which glycolysis (and ATP production) would stop. Lactate fermentation is the anaerobic carbohydrate breakdown pathway that produces ATP and lactate. The end product of lactate fermentation is lactate. The end product of alcoholic fermentation is ethanol. Both pathways have a net yield of two ATP per glucose molecule. The ATP forms during glycosis.