biology unit 2: chemistry unit objectives

compound

compound

a combination of simple molecules

ionic bond

(chemical bond) 2 or more atoms exchange one or more electrons; e.g. Na+Cl-

covalent bond

(chemical bond) 2 or more atoms share electrons; e.g. CH4

solution

a liquid consisting of two or more substances evenly mixed

solute

the dissolved substance

pH scale

"Potential of Hydrogen" lower number (1-7) = more acidic, higher number = more basic (7-14), 7 = neutral

acid

proton donor (H+) which lowers pH of a solution and taste sour

base

(alkali) - proton acceptor (OH-) that raises pH of a solution and they taste bitter

monomer

the smaller units (of simple molecules) join together to form polymers

polymer

chain of monomers linked together

starch

sugar

protein

each molecule has amine (NH2), acid (COOH), and CH, but the varying R group = the AMINO group

amino acid

nucleic acid

polymers (chain of nucleotides) build nucleic acids -so more than one of these shown nucleotides would be required to form a nucleic acid "NUCLEOTIDES BUILD NUCLEIC ACIDS IN THE NUCLEUS"

nucleotide

triglyceride

1. The atomic number of carbon is 6. Its nucleus must contain:

d) 6 protons and no electrons (protons and neutrons are found inside the nucleus, while electrons are outside of it)

2. The second orbital shell of an atom can hold _____ electrons.

e) 8

3. A covalent bond is formed when:

d) two atoms share electrons

4. Which of the following phenomena is most likely due to the high cohesiveness of water?

b. The fishing spider can walk across the surface of liquid water. (water is basically very strong)

5. Water can absorb and store a large amount of heat while increasing only a few degrees in temperature. Why?

a) The heat must first be used to break the hydrogen bonds rather than raise the temperature.

6. A chemical compound that releases H+ into a solution is called:

c) an acid

7. Which of the following foods is not a significant source of complex carbohydrates?

a) fresh fruit

8. Sucrose (table sugar) and lactose (the sugar found in milk) are examples of:

d) disaccharides

9. Which of the following statements about starch is incorrect?

c) Starch tastes sweet because it is made from glucose.

10. Which of the following statements about fiber is incorrect?

b) Fiber in the diet slows the passage of food through the intestines.

12. An unsaturated fatty acid is one in which:

a) carbon-carbon double bonds are present in the hydrocarbon chain.

13. Which statement about phospholipids is incorrect?

a) Because their phosphate groups repel each other, they are used as organisms' chief form of short-term energy.

15. Dietary proteins:

a) are considered "complete" only if they contain the 8 essential amino acids required by humans.

16. The primary structure of proteins is often described as amino acids connected like beads on a string. In this same vein, which of the following images best describes a protein's quaternary structure?

a) threads in a cloth

17. Which of the following statements about enzymes is incorrect?

e) Enzymes undergo a permanent change during the reactions they promote.

18. Which of the following nucleotide bases are present in equal amounts in DNA?

e) adenine and thymine

19. Which type of macromolecule contains an organism's genetic information?

d) DNA

20. All of the following are features of RNA except:

b) a coiled double-stranded structure.

1.) Describe what a periodic table is and what the numbers and symbols represent. (Chpt. 2.1)

-periodic table is an arrangement of elements in the order of their atomic number -element symbol in the center = abbreviation of the element's name -atomic number at the top left side = the number of protons found in the atom's nucleus -atomic mass at the very bottom = combined mass of the atom's protons and neutrons

2.) What levels of a biological system are the focus for most the 1st semester? Give examples of things we will study at these levels.

-focusing on a biological system at the CHEMICAL level -e.g. molecules, macromolecules, atoms, bonds, elements

3.) Identify carbon, hydrogen, oxygen, and nitrogen as the primary elements of life in relation to the percentage of these elements that build a human body. (Chpt. 2.1)

-builds 96.3% of a human body O - 65.0 C - 18.5 H - 9.5 N - 3.3

4.) Defend the importance of water to life systems and describe what about its shape gives it these characteristics. (Chpt. 2.4-2.6)

-water molecules easily form hydrogen bonds, giving water great cohesiveness -hydrogen bonding = high surface tension and capillarity -high specific heat = good coolant & good antifreeze -good capillarity means that organisms can easily access water, even throughout challenging environments -a universal solvent due to its polarity (charges)

5.) Compare and contrast the different types of chemical bonds. (Chpt. 2.3)

1. ionic - exchanging electrons, 1 atom steals & 1 atom loses

2. covalent - share electrons because neither atom is strong enough to steal one from the other

(these are INTRAmolecular, inside)

3. hydrogen - occurs when hydrogen atom that's COVALENTLY bound to a highly electronegative atom experiences the electrostatic field of another highly electronegative atom nearby.

6.) Explain in detail a solution (its makeup) and the pH scale in terms of the percentage of ions present in a solution. (Chpt. 2.6)

-acidic or basic based on positive ions and negative ions in solution -more positive ions LOWER the pH of a solution = acidic (proton donor) -more negative ions RAISE the pH of a solution = basic (proton acceptor, accepting all the protons so it's left with neg. ions)

7.) Study and review the organic compound review grid and know the major macromolecules. (Chpt. 2.7-2.21)

CARBOHYDRATES: function: quick energy storage, build structures monomer(s): single sugar (glucose) elements: (CH2O)n ex: mono: glucose, fructose, galactose; di: sucrose, maltose, lactose; poly: starch GLYCOGEN, cellulose, chitin saccharide means sugar!!!

PROTEIN: function: move, fight infection, catalyze reactions, build, toxins, messenger monomer(s): amino acid (20) elements: CHON ex: protein channels, motor proteins, hemoglobin & myoglobin, antibodies, enzymes (catalase, lactase), hormone (insulin)

NUCLEIC ACIDS: function: store information monomer(s): nucleotides (4) elements: CHONP ex: DNA - 2 chains RNA - 1 chain

LIPIDS: function: long term energy storage, insulation, padding, messengers building blocks: triglyceride: GLYCEROL + 3 fatty acids + cholesterol elements: CHOP ex: fat, oil, wax, phospholipids, testosterone, estrogen, progesterone

8.) Discuss in detail what an enzyme is, how it works, and how it affects reaction rates. (Chpt. 2.17-2.18)

-enzyme = protein that can be used again & again in reactions -binds with only CERTAIN substrates that it wants on its active site (like a lock & a key) -increases reaction rates by lowering the activation energy (shortens minimum "push" energy so total reactions increase and react faster)

9.) Differentiate the uses and purposes of reagents such as iodine, benedicts, and biurets. (LAB)

-they're all used to identify macromolecules within a substance -iodine = starch -bendedicts = sugar -biurets = protein