Studied by 2 peopleCh. 1,2,3
What is biology?
the scientific study of life
What are the properties that all living things share? List them.
Order
Energy and Matter Processing
Reproduction
Growth and Development
Response to the Environment
Evolutionary Adaptations
Are viruses alive? Explain your answer.
Viruses do display some of life’s properties—each has a highly ordered structure, for example.
Although viruses can infect a wide variety of organisms, they cannot reproduce or carry out many other of life’s processes outside of a host cell.
The idea is not settled, but many biologists agree that viruses are not alive, existing in a state between living organisms and nonliving chemicals.
List the basic steps in the scientific method.
Observation
Question
Hypothesis
Experiment
Results
Conclusion
What is a hypothesis?
a proposed explanation for a set of observations.
A hypothesis should be testable, falsifiable, and immediately lead to predictions that can be tested.
How are hypothesis and theories different?
unlike a hypothesis (proposed explanation), every scientific theory is backed up by a wealth of supporting evidence.
What is a placebo?
a medically ineffective treatment that allows the placebo group to serve as a negative control for the real drug.
What is a control group? Why is it important?
is used to establish a baseline for an experiment.
Control groups are important because a scientist will be able to determine which changes or outcomes come from the experiment and not another variable.
What is pseudoscience?
any field of study that is falsely presented as having a scientific basis.
How can you recognize pseudoscience? How is it different from science?
What is peer review?
he evaluation of work by impartial, qualified, often anonymous experts who are not involved in that work.
What is a primary source?
is original material presented for the first time by the person(s) who performed the research.
What is a secondary source?
is a description or review of primary sources, often containing commentary.
What is an element?
substances that cannot be broken down into other substances by chemical reactions.
What is an atom?
the smallest units that retain all of the properties of their type of matter.
What is a proton?
A subatomic particle with a single unit of positive electrical charge, found in the nucleus of an atom.
What is a neutron?
An electrically neutral particle (particle with no electrical charge), found in the nucleus of an atom.
What is an electron?
A subatomic particle with a single unit of negative electrical charge. One or more electrons move around the nucleus of an atom.
What is an atom’s atomic number?
The number of protons in an atom of a given element.
What is an atom’s atomic weight?
(Atomic Mass) The total mass of an atom
How do you calculate the number of electrons of a specific element?
In a neutral atom, the number of electrons is equal to the number of protons.
Knowing the atomic weight of an atom of a given element, how do you find out the number of neutrons?
Atomic mass - Atomic number = neutrons
What is an isotope?
The same number of protons and electrons but a different number of neutrons.
Which particles allow atoms to interact with each other to form bonds?
Valence electrons
What is the valence shell of an atom?
The outermost shell of an atom that contains valence electrons.
What is an ion?
an atom or group of atoms that has acquired a charge by the gain or loss of electrons.
What is a molecule?
A group of two or more atoms held together by covalent bonds.
What is a covalent bond?
An attraction between atoms that share one or more pairs of outer-shell electrons.
What is electronegativity?
A measure of an atom's ability to attract shared electrons to itself.
What does hydrophilic mean?
“Water Loving“, having a tendency to mix with, dissolve in, or be wetted by water.
What molecules are hydrophilic?
Polar
What does hydrophobic mean?
“Water-fearing”; pertaining to nonpolar molecules (or parts of molecules), which do not dissolve in water.
What is an ionic bond?
An attraction between two ions with opposite electrical charges. The electrical attraction of the opposite charges holds the ions together.
What is a hydrogen bond?
A type of weak chemical bond formed when a partially positive hydrogen atom from one polar molecule is attracted to the partially negative atom in another molecule (or in another part of the same molecule).
Compare covalent, ionic, and hydrogen bonds. Which is strongest? Weakest?
Ionic bond > Covalent bond > Hydrogen bond
Why are hydrogen bonds important?
They are essential for the structure of water and other molecules.
What are the main properties of water? List them.
Hydrogen Bonding in Water
Ice Floating
Water as a Solvent
Temperature Regulation
Temperature Regulation
What types of substances does water dissolve?
Polar substances
Unlike nearly all other liquids, water expands when it freezes. Why does this happen?
When water molecules freeze, they move apart, forming a rigid network of long-lasting hydrogen bonds.
How are cohesion and adhesion different?
Cohesion is the attraction between molecules of the same kind. Adhesion is The clinging of one substance to another, such as water to plant cell walls, by means of hydrogen bond.
What is pH?
A measure of the acidity of a solution. pH stands for potential hydrogen and refers to the concentration of hydrogen ions.
0 = most acidic
14 = most basic
What is a buffer?
A chemical substance that resists changes in pH by accepting hydrogen ions from or donating hydrogen ions to solutions.
What is an organic compound?
Molecules that contain carbon bonded to other elements. (Skeleton of carbon atoms)
What is a functional group?
A group of atoms that form the chemically reactive part of an organic molecule. A particular functional group usually behaves similarly in different chemical reactions.
What is a monomer?
A chemical subunit that serves as a building block of a polymer.
What is a polymer?
A large molecule consisting of many identical or similar molecular units, called monomers, covalently joined together in a chain.
What is a carbohydrate?
A biological molecule consisting of a simple sugar (a monosaccharide), two monosaccharides joined into a double sugar (a disaccharide), or a chain of monosaccharides (a polysaccharide).
What is a monosaccharide?
The smallest kind of sugar molecule; a single-unit sugar; also known as a simple sugar. Monosaccharides are the building blocks of more complex sugars and polysaccharides.
What is glycogen?
A complex, extensively branched polysaccharide made up of many glucose monomers; serves as an energy-storage molecule in liver and muscle cells.
What is a disaccharide?
A sugar molecule consisting of two monosaccharides linked by a dehydration synthesis reaction.
What is a polysaccharide?
A (complex) carbohydrate polymer consisting of many monosaccharides (sugars) linked by covalent bonds.
Give an example of a complex carbohydrate.
Foods like potatoes have starch which is a complex carb.
Give an example of a sugar.
Glucose and fructose are examples of sugars.
What is the relationship between sugar, obesity, and type II diabetes?
High quantities of sugar can lead to both diabetes and obesity, especially when someone does not exercise.
Are monosaccharides considered sugars, or complex carbohydrates?
Sugar
Are polysaccharides considered sugars, or complex carbohydrates?
Complex carbohydrates
What is starch?
A storage polysaccharide found in the roots of plants and certain other cells; a polymer of glucose.
What is chitin?
A structural polysaccharide found in many fungal cell walls and in the exoskeletons of arthropods.
What is cellulose?
A large polysaccharide composed of many glucose monomers linked into cable-like fibrils that provide structural support in plant cell walls. Because cellulose cannot be digested by animals, it acts as fiber, or roughage, in the diet.
What is a lipid?
An organic compound consisting mainly of carbon and hydrogen atoms linked by nonpolar covalent bonds and therefore mostly hydrophobic and insoluble in water. Lipids include fats, waxes, phospholipids, and steroids.
What is a fat?
In food/chemistry: a molecule of glycerol and three molecules of fatty acids creates a fat (triglyceride). In our bodies: adipose tissues is known as body fat.
How are saturated and unsaturated fats different?
Saturated fats have the maximum number of hydrogens along the fatty acid tail, which corresponds to all single chemical bonds in the chain. As a result, the fatty acid tails in saturated fats are straight. This shape allows them to easily stack together and form solids, so highly saturated fats tend to be solid at room temperature. Saturated fats are found in highest quantities (but not exclusively) in animal products.
Unsaturated fats have one or more double bonds in the fatty acid tail, causing them to have fewer than the maximum number of hydrogens. As a result, the fatty acid tails of unsaturated fats have a bend or kink at each double bond, giving the molecule a twisted shape. This prevents them from stacking easily, so unsaturated fats tend to be liquid at room temperature. Unsaturated fats are found in greatest quantities (but not exclusively) in vegetable and fish oils.
Which is better for your health: Saturated fats vs. Unsaturated fats?
Unsaturated fats are healthier for you.
What are trans fats?
Unsaturated fatty acids produced by the partial hydrogenation of vegetable oils and present in hardened vegetable oils, most margarines, many commercial baked foods, and many fried foods. This type of unsaturated fat does not occur naturally and are quite unhealthy.
What is hydrogenation?
The process of converting unsaturated fats to saturated fats by adding hydrogen.
What are steroids and why are they important?
Steroids are lipids that contain four fused chemical rings made primarily of carbon. Examples include cholesterol, testosterone, and estrogen. Steroids are important because it includes our sex hormones.
What is a phospholipid?
A molecule that is a constituent of the inner bilayer of biological membranes, having a hydrophilic head and a hydrophobic tail.
What is a protein?
A biological polymer constructed from amino acid monomers. Proteins perform most of the tasks required for life. Each kind of protein has a unique shape that determines its function.
What is an amino acid?
An organic molecule containing a carboxyl group, an amino group, a hydrogen atom, and a variable side group (also called a radical group or R group); serves as the monomer of proteins.
What is a nucleic acid?
A polymer consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular structures and activities. The two types of nucleic acids are DNA and RNA.
What is a nucleotide?
An organic monomer consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. Nucleotides are the building blocks of nucleic acids.
What are the two types of nucleic acids?
DNA and RNA
What is a cell?
A basic unit of living matter separated from its environment by a plasma membrane; the fundamental structural unit of life.
How are prokaryotic and eukaryotic cells different?
What is a ribosome?
A cellular structure consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm. The ribosomal subunits are constructed in the nucleolus.
What is an organelle?
A membrane-enclosed structure with a specialized function within a eukaryotic cell.
What does the endosymbiosis theory state?
Eukaryotic cells evolved from prokaryotic cells. Its believed that parts of one cell joined another.
What two organelles originated through endosymbiosis?
mitochondrion and the chloroplast
What is the main function of the plasma membrane?
Membranes regulate the passage of materials into and out of the cell. They also keep the cell internals separated from the outside environment.
What is the function of the nucleus?
An atom’s central core, containing protons and neutrons. (2) The genetic control center of a eukaryotic cell. Contains most of the cells DNA.
What is the function of the cytoskeleton?
A meshwork of fine fibers in the cytoplasm of a eukaryotic cell; includes microfilaments, intermediate filaments, and microtubules. Provides structure for the cell.
What is the function of the mitochondria?
An organelle in eukaryotic cells where cellular respiration occurs. Enclosed by two concentric membranes, it is where most of the cell’s ATP is made.
What is the function of lysosomes?
A digestive organelle in eukaryotic cells; contains enzymes that digest the cell’s food and wastes.
What is the main function of the rough endoplasmic reticulum?
To produce proteins.
What are the two main functions of the smooth endoplasmic reticulum?
Synthesis of molecules such as lipids and metabolism of exogenous substances, such as drugs or toxins.
What are the main functions of the Golgi apparatus?
To modify, store, and distribute proteins.
What organelles are only present in plant cells? What is their function?
chloroplasts- convert light energy into food energy during photosynthesis
cell walls- helps cell keep its shape.
central vacuole- a storage sac that stores a variety of substances such as water and nutrients.
What substances pass easily through a plasma membrane? Which ones don’t?
Small nonpolar, uncharged substances pass through easiest. Large polar molecules and ions have the hardest time.
What is passive transport?
When a substance moves across a membrane from an area where its concentration is higher to an area where its concentration is lower (ALWAYS INVOLVES DIFFUSION). This requires no energy. Simple diffusion, facilitated diffusion and osmosis are subsets of this.
What is diffusion?
The movement of molecules from an area of higher concentration to an area of lower concentration.
What does DOWN a concentration gradient mean?
Moving from an area of high concentration of some entity to an area of low concentration.
What does AGAINST a concentration gradient mean?
Moving from an area of low concentration to an area of high concentration.
Solute
The component that is dissolved in a solvent
Solvent
The dissolving agent in a solution.
Solution
A liquid consisting of a homogeneous mixture of two or more substances: a dissolving agent, the solvent, and a substance that is dissolved, the solute.
What is simple diffusion?
The movement of molecules from an area of higher concentration to an area of lower concentration that is allowed be the cell membrane. Small and nonpolar molecules do this. This is a type of passive transport.
What is facilitated diffusion?
The passage of a substance across a biological membrane down its concentration gradient, aided by specific transport proteins. Polar molecules use this.
What is osmosis?
The diffusion of water across a selectively permeable membrane.
Hypotonic
Has a lower solute concentration of fluid, sugars and salt than inside the cell. Water will flow into the cell
Hypertonic
Has a higher solute concentration of fluid, sugars and salt than inside cell. Water will flow out of the cell.
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