Microbiology 145 midterm

Question 1

World-changing scientific contributions of Leeuwenhoek

Answer 1

Lens grinder, first discovered the bacterial world, handmade microscopes.

Question 2

Define “microbes” via definition derived by Leeuwenhoek

Answer 2

“All organisms that are too small to be seen without a microscope”

Question 3

List six groups of microorganisms

Answer 3

• Fungi
• Protozoa
• Algae
• Bacteria
• Archaea
• Small Multicellular animals

Question 4

Differentiate between prokaryotic and eukaryotic

Answer 4

• Prokaryotic: Any unicellular organism that LACKS a nucleus, (Bacteria & Archaea)
• Eukaryotic: Any organism made up of cells containing a nucleus composed of genetic material surrounded by a distinct membrane. (animals, plants, algae, fungi, protozoa)

Question 5

4 questions which propelled research into the “Golden Age of Microbiology”

Answer 5

• Is spontaneous generation of microbial life possible?
• What causes fermentation?
  
  • Heating liquid to kill contaminating bacteria without changing the liquid’s basic qualities so it can be consumed.
• What causes disease?
• How can we prevent infection and disease?

Question 6

4 steps in the scientific method of investigation

Answer 6

• Group of observations leads a scientist to ask a question about some phenomenon
• Generate a hypothesis
• Design and conduct experiment to text hypothesis
• Accept, reject or modify hypothesis

Question 7

Significance of Pasteur’s fermentation experiences relative to our world today

Answer 7

Luis Pasteur’s fermentation experiment is relative to our world today because he developed “Pasteurization” which we use frequently. He took grape juice and heated it up just enough to kill most contaminating bacteria without changing the juice’s basic qualities, so that it could be inoculated with yeast to ensure the alcohol fermentation occurred. This began the field of Biotechnology: microbes are intentionally used to manufacture products

Question 8

Describe the research in public health which led to more effective disease prevention

Answer 8

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Question 9

List the four questions that are currently used to drive research in the “Age of Modernism”

Answer 9

• What are the basic chemical reactions of life
• How do genes work?
• What roles do microorganisms play in the environment?
• How do we defend against disease?

Question 10

Define the Atom

Answer 10

Atoms: smallest chemical unit of matter

• Composed of positively charged protons, and negatively charged neutrons
• Electrons: negatively charged particles that exist around the atom nucleus

Question 10

Electron configuration

Answer 10

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Question 11

Define: Isotope

Answer 11

atoms of an element that differ in the number of neutrons

Question 12

Configuration of electrons in a stable atom

Answer 12

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Question 14

Define: Nonpolar covalent bond

Answer 14

sharing of electrons between atoms of similar electronegativities, so that no poles exist

Question 15

Define: polar covalent bond

Answer 15

Unequal sharing of electrons

Question 16

Define: Ionic bond

Answer 16

.Atoms with opposite charges attract and form ionic bonds

Question 17

Define: Molecule

Answer 17

two or more atoms held together by chemical bonds

Question 18

Define: Compound

Answer 18

if a molecule contains atoms of more than one atom

Question 19

3 types of chemical reactions found in living things

Answer 19

• Synthesis: involve the formation of larger more complex molecules
• Decomposition: reverse of synthesis reactions; break bonds within larger molecules to form smaller atoms, ions, and molecules
• Exchange: Involve breaking and forming covalent bonds. Both endothermic and exothermic steps

Question 20

Acid

Answer 20

Substance that dissociates into one or more hydrogen ions and one or more anions. (lemon juice, black coffee, tea)

Question 21

Base

Answer 21

Molecule that binds with H+ when dissolved in water (baking soda/bleach)

Question 22

Salt

Answer 22

Compound that dissociates in water into cations and anions other than H+ and OH-.

Question 23

Unique characteristics of water that make it useful in human biology

Answer 23

• Surface tension
• Solvent
• Wide range of temperature
• Can absorb heat and evaporate
• Participate in many reactions as reactant of product

Question 24

Role of a buffer

Answer 24

-Substances that prevent drastic changes in pH

Question 25

Lipids

Answer 25

hydrophobic organic molecule

-Fats, waxes, phospholipids, steroids

Question 26

Discuss the 4 principle functions of living cells

Answer 26

• Growth
• Reproduction
• Responsiveness
• Metabolism

Question 27

Compare & Contrast eukaryotic and prokaryotic cells.

Answer 27

Eukaryotic
- Algae, Protozoa, Animals & Plants
- Nuclear envelope surrounds DNA to make a nucleus
- Membrane-bound organelles
- Large in size (compared to prokaryotes)
- 80s Ribosomes
- Cytoskeleton: cell structure, organize organelles
Prokaryotic
- Bacteria & Archaea
- No membrane bound nucleus
- Make proteins simultaneously from reading genetic code
- Different macromolecules (lipids, carbohydrates)
- Non-membranous organelles
- May have inclusions or endospores
- 70s Ribosomes
- Cytoskeleton: cell structure

Question 28

Glycocalyses

Answer 28

gelatinous substance that surrounds the outside of the cell

Question 29

Flagella

Answer 29

long locomotive structure extending beyond the surface of cell for mobility

Question 30

Fimbriae

Answer 30

sticky, bristle-like projections used to adhere to one another or substances in the environment.
helps form biofilms

Question 31

Pili

Answer 31

Type of fimbria which is used by bacteria to transfer DNA to another cell

Question 32

Gram + Cell wall structure

Answer 32

• Thick layer of peptidoglycan outside cytoplasmic membrane
• Techoic acids and lipotechoic acids
• Techoic acids have – charge
• Some have waxy lipids which help them survive drying out

Question 33

Gram - Cell wall structure

Answer 33

• Thin layer of peptidoglycan
• Second layer
• Inner: phospholipid + protein
• Outer: lipopolysaccharide
• Lipid A: componenet of LPS aka Endotoxin
• Porins: proteins that form channels in second layer
• Periplasmic space: area between the membrane

Question 34

Describe the phospholipid bilayer found in cytoplasmic membranes and its function

Answer 34

• Phospholipid bilayer: 2 layers of polar molecule and contains integral proteins
• Controls what enters/exits the cell. Defines inside vs. outside of cell. Selectively permeable. Creates a concentration gradient. Electrical gradient.

Question 35

Diffusion

Answer 35

Net movement of a chemical down it’s concentration gradient

Question 36

Hypotonic

Answer 36

concentration of solute is lower in comparison

Question 37

Hypertonic

Answer 37

concentration of solute is higher

Question 38

Isotonic

Answer 38

equal concentration of solutes

Question 39

Facilitated diffusion

Answer 39

Proteins in membrane provide a pathway for chemicals to flow

Question 40

Osmosis

Answer 40

The diffusion of water across the membrane

Question 41

Active transport

Answer 41

The movement of a substance against it’s electrochemical gradient via carrier proteins and requiring cell energy from ATP

Question 42

Uniport

Answer 42

one substance transported at a time

Question 43

Antiport

Answer 43

Simultaneous but opposite, transport of two chemicals

Question 44

Group Translocation

Answer 44

Active process by which a substance being actively transported across a cell membrane is chemically changed during transport