Exam 1 pt 1

Question 1

Compare adhesion and cohesion

Answer 1

— adhesion= when water molecules stick to something else through hydrogen bonds
— cohesion= like molecules stick together (water molecules)

Question 2

Define acids and bases, give examples

Answer 2

• acid= low pH, donates H+ ions,
• base= high pH, receives H+ ions and donates OH- ions, sodium hydroxide

Question 3

• What are the two main types of protein secondary structure? What determines the secondary structures?

Answer 3

• Alpha helix
• Beta pleated sheet
  
  • The secondary structures are determined by protein shape due to the hydrogen bonds between the amino acids

Question 4

• Define hydrophobic vs hydrophilic, which are polar?

Answer 4

• Philic- water loving, polar (dissolve in water)
• Phobic- water fearing, non polar

Question 5

Give an example of a compound (a molecule made up of two or more DIFFERENT elements)

Answer 5

H2O

Question 6

Compare DNA and RNA

Answer 6

• DNA- deoxyribose, lacks oxygen, double stranded helix, A,T,C,G
• RNA- ribose, single stranded helix, A,U,C,G

Question 7

What determines a protein’s primary structure?

Answer 7

• The sequence of nucleotides determined by genes

by the gene corresponding to the protein

Question 8

Describe the structure of the plasma membrane of all organisms. What types of substances is it permeable to?

Answer 8

• Hydrophilic phosphate head, hydrophobic lipid tail (phospholipid bilayer) with proteins in the hydrophilic heads (cannot dissolve in membrane)
  
  • Hydrophobic substances can pass through, they dissolve in the membranes

Question 9

Define IV, DV Constants and Controls

Answer 9

• IV- independent variable (purposeful change)
  
  • DV- dependent variable (affected by purposeful change, responds to change)
  • Constants- factors that do not change
  • Controls- group that does not receive the independent variable, standard for comparison

Question 10

Compare the number of protons and electrons in an anion, give example

Answer 10

• More electrons than protons (gain electrons to become more stable)
  
  • Sulfur, Oxygen, Chlorine, Iodine, etc.

Question 11

Compare Prokaryotes and Eukaryotes

Answer 11

• Eukaryotes possess a nucleus and other organelles (membrane bound structures within the cell), larger
• Prokaryotes= archaea and bacteria
  
  • Both are equally alive

Question 12

Explain how reductionism and emergent properties compliment each other

Answer 12

• Reductionism= an approach that reduces complex systems to simpler components
  
  • Emergent properties= novel properties that emerge at each level that were absent from the previous one
  • Reductionism helps us identify the components but to really understand how living systems work, we have to understand where they came from

Question 13

• Define anabolism and catabolism

Answer 13

• Anabolism= building up, joining smaller molecules to make larger ones (dehydration synthesis)
  
  • Catabolism= tearing down, breaking down big molecules to create smaller ones

Question 14

• Give an example of an atom that would form a cation. Why and how do they form?

Answer 14

• Contain less electrons in the valence and it is easier to lose them than gain more, need to become stable

happens when an atom loses one or more electrons
* Calcium, magnesium

Question 15

Compare covalent and ionic bonds. Give an example of a molecule and an ionic compound

Answer 15

• covalent= molecules (water, H20), sharing of electrons
  
  • Ionic bonds= ionic compounds (salts), donating (transfer) of electrons

Question 16

• Which four elements make up most of living matter?

Answer 16

Carbon, Hydrogen, Nitrogen, Oxygen

Question 17

• All Sulfur atoms have 16 electrons, what is its atomic number?

Answer 17

• 16, protons=electrons, number of protons or electrons is equal to the atomic number

Question 18

• Mass numbers are always a whole number yet atomic mass is always a decimal. Explain

Answer 18

• Mass # = # p+# n
  
  • Atomic mass= average number of protons and neutrons for all isotopes on the planet

Question 19

• How many covalent bonds can carbon atoms form? Why is this essential to life on earth?

Answer 19

• 4 bonds* Explains the variety and complexity of molecules in living systems due to the long carbon chains it can make

Question 20

• What does it mean to be a strong base?

Answer 20

• It will dissociate completely, most compounds will separate into the individual ions (NaOH - Na+ + OH-)

Question 21

What are the three types of isomers? Give an example of each

Answer 21

• Same chemical formula but atoms are arranged differently
  
  • Structural- different placements of the atoms
  • Cis-trans- requires a C=C (carbon-carbon double bond)
  • Enatomer- mirror images

Question 22

Draw the following functional groups: alcohol, amino, carboxyl, methyl, and phosphate

Answer 22

• alcohol= OH
  
  • Amino= NH2
  • Carboxyl= COOH
  • Methyl= CH3
  • Phosphate= OPO3-

Question 23

Why does ice float in liquid water?

Answer 23

• The hydrogen bonds in ice are more structured and spread out, making ice less dense than water and allowing them to float

Question 24

Draw a water molecule and explain why it is polar

Answer 24

• Two regions of opposing partial charges (O= partial negative charge, H2= partial positive charge)

Question 25

What does specific heat refer to? Why is water’s so high?

Answer 25

• The amount of energy a substance can absorb before it changes temperatures
  
  • A lot of energy is absorbed prior to the breaking of hydrogen bonds, so it takes much more energy to break them