Cell Chemistry (and introduction material)

Question 1

What about microbes do people study

Answer 1

Biochemistry morphology physiology genetics ecology (interaction of microbes) evolution

Question 2

Aspects of Microbiology

Answer 2

1. Understanding basic life processes
   - microbes are excellent models for understanding cellular processes in unicellular and multicellular organisms (understanding transcription, translation, and metabolism)
2. Applying knowledge learned from microbes to benefit humans
   - microbes play an important role in medicine, agriculture, and industry

Question 3

Importance of Microorganisms

Answer 3

• oldest form of life
• microbes found almost everywhere (most in ocean/soil)
• largest mass of living material on Earth (make up 1/3-1/2 of world’s biomass)
• help carry out major processes for biogeochemical cycles (nitrogen and carbon cycle)
• other life forms require microbes to survive -they cause many human/animal diseases
• cause most plant disease
• cause 99.99% of all decomposition
• many useful products are made by/with/contain microorganisms

Question 4

Domain Bacteria

Answer 4

• usually single-celled
• majority have peptidoglycan cell walls
• lack a membrane-bound nucleus
• found almost everywhere and some in extreme environments
• cyanobacteria and some others produce significant amounts of oxygen

Question 5

Domain Archaea

Answer 5

• distinguished from Domain Bacteria by unique rRNA sequences
• lack peptidoglycan cell walls
• have unique cell membrane lipids -many live in extreme environments

Question 6

Domain Eukarya

Answer 6

cells have organelles and are specialized. Organisms in this domain are multicellular

Protists- generally larger than Bacteria and Archaea (algae, protozoa, slime molds, water molds)

Fungi- chemo heterotroph absorbers (gain energy through oxidation of electron donors in their environment)

Question 7

Acellular Infectious Agents

Answer 7

not consisting of cells

1. Viruses -smallest of all microbes -requires host cell to replicate -cause ranges of diseases, some cancers
2. Viroids and Virusoids -infectious agents composed of RNA
3. Prions -infectious proteins

Question 8

Antony van Leeuwenhoek (1632-1723)

Answer 8

first person to observe and accurately describe microorganisms (used simple microscope)

Question 9

Conflict over spontaneous generation

Answer 9

spontaneous generation

• living organisms (microbes) could develop from nonliving or decomposing matter
• This theory was discredited by Redi in the 17th century because he showed that maggots on decaying meat came from fly eggs

Question 10

Louis Pasteur

Answer 10

helped disprove spontaneous generation Conducted experiment that: had two flasks with sterile liquid with bent necks preventing air from coming into flasks. flask with broken neck and exposed to air grew microbes and flask that wasn’t exposed to air did not grow microbes Other contributions: demonstrated that alcohol fermentation was a result of microbe activity. developed the process of pasteurization. developed vaccines for chicken pox, anthrax, and rabies

Question 11

Robert Koch (1843-1910)

Answer 11

established relationship between bacteria and certain illnesses

Koch’s Postulates:

• the microorganism must be present in every case of the disease but absent from healthy individuals
• the suspected microorganism must be isolated and grown in a pure culture
• the same disease must result when the isolated microorganism is inoculated into a healthy host
• the same microorganism must be isolated again from the diseased host

Limitations of Postulates:

• some organisms cannot be grown in pure culture (some cellular and all viruses)
• using humans in completing postulates is unethical

Question 12

Ionic Bonds

Answer 12

• bonds formed by the attraction of oppositely charged ions (cation and anion)
• gain or loss of electrons forms ions
• electrical polarity of water molecules can disrupt forces holding ions together
• electrons aren’t shared just an attraction

Question 13

Covalent Bonds

Answer 13

strong bond where electrons are shared between atoms to fill valence shell of atoms

• single bonds allow rotation
• double bonds do not allow rotation but allow bending -triple bonds aren’t found in biological systems

*whether polar or nonpolar the net charge of bond is zero (no ions)

Question 14

Hydrogen Bonds

Answer 14

weak bonds that form due to electrostatic interactions between hydrogen atoms and more electronegative atoms. (proteins and amino acids)

• multiple hydrogen bonds impart considerable stability to molecules
• play major roles in biological properties of proteins
• plays major role in the solubility and other properties of water

Question 15

Van Der Waals forces

Answer 15

short lived attraction when molecules are very close important in: -enzymes binding substrates and membrane fluidity

Question 16

Phosphoanhydride

Answer 16

ATP

Significance: energy metabolism

Question 17

Hydroxyl Group

Answer 17

alcohol (OH-)

-more polar/water soluble

Example: glucose

Significance: lipids/carbohydrates

Question 18

Carboxyl group

Answer 18

can act as an acid

Example: acetate

Significance: organic, amino, or fatty acids. lipids or proteins

Question 19

Methyl group

Answer 19

Question 20

Acetyl group

Answer 20

Question 21

Hydrocarbons

Answer 21

nonpolar and hydrophobic

• made up of ONLY hydrogen and carbon
• ane suffix

Question 22

Amino acid

Answer 22

NH2 is the amino group

OH- is the carboxylic acid group (makes it more polar and water soluble)

R is functional group

Question 23

Carbohydrates

Answer 23

Play important roles in cell walls and as energy storage molecules

Monomers= monosaccharides and disaccharides (sugars)

*organic compounds that contain carbon, hydrogen, and oxygen at a ratio of 1:2:1

-polar molecules (hydrophilic)

Most biologically significant ones are:

1. Pentoses (5 carbon sugars) - backbones of nucleic acids
2. Hexoses (6 carbon sugars) - monomeric constituents of cell wall polymers and energy reserves

Question 24

Sugar derivatives

Answer 24

when other chemical substances replace one or more of the hydroxyl groups on the sugar (acetyl group replaces hydroxyl group on glucose)

Question 25

Polysacchrides

Answer 25

glycosidic bonds: covalent bonds linking adjacent sugars together possible bonds are alpha and beta bonds (crosses plane of ring structure) -different bonds mean different functional properties

Question 26

Alpha 1, 6-Glycosidic bond

Answer 26

Question 27

Alpha-1, 4-Glycosidic Bond

Answer 27

Question 28

Beta-1, 4-Glycosidic bond

Answer 28

Question 29

Triglycerides

Answer 29

composed of 3 fatty acid tails bonded to 3 carbon alcohol (glycerol) function: energy storage - contains ester bonds between glycerol and fatty acids - fatty acids consist of carboxyl group and hydrocarbon chain

Question 30

Complex lipids

Answer 30

simple lipids that contain additional elements such as P, N, S, or hydrophilic organic compounds like sugars example: phospholipids- contains 2 fatty acids, glycerol, phosphate group, and something attached to phosphate (ethanolamine)

Question 31

Nucleic Acids, DNA, RNA

Answer 31

Nucleid Acid: polymer of nucleotides DNA: polymer of deoxribonucleotides (genetic material in all cells and some viruses) RNA: polymer of ribonucleotides (plays role in protein synthesis in all cells, and is genetic material for most viruses)

Question 32

Sterols and Hopanoids

Answer 32

- lipids that provide membranes with rigid structure sterols: found in all eukaryotes but few prokaryotes hopanoids: found in many prokaryotes, but no eurkaryotes

Question 33

Nucleotides

Answer 33

nitrogen base attached to 5-carbon sugar by N-glycosidic bond and bonded to a phosphate - major components of nucleic acids - key forms of chemical energy (ATP) - carriers of sugars in biosynthesis or polysacchrides - regulatory molecules for certain enzymes or metabolic events

Question 34

N-glycocitic bond

Answer 34

bond between adenine and a sugar

Question 35

Glycosidic bonds

Answer 35

covalent bonds linking adjacent sugars together \*alpha or beta orientations

Question 36

Phosphoester bond

Answer 36

phosphate attached to a sugar (nucleotides) \*phosphodiester bond is a covalent bond that connects two adjacent nucleotides on the same strand

Question 37

2 classes of nucleic acid nitrogen bases

Answer 37

Purine bases: (adenine and guanine) contain two fused heterocyclic rings - Adenine (A) \*in DNA and RNA - Guanine (G) \*in DNA and RNA Pyrimidine bases: (thymine, cytosine, and uracil) contain a single six-membered heterocyclic ring - Cytosine (C) \*in DNA and RNA - Thymine (T) \*in DNA only - Uracil (U) \*in RNA only

Question 38

ATP

Answer 38

Question 39

Proteins

Answer 39

made up of amino acids - side chains of amino acids impart chemical properties - amino acids with similar chemical properties are grouped into families - a protein is a functional unit consisting of one or more polypeptides

Question 40

Amino Acids

Answer 40

Two important functional groups: - carboxylic group (-COOH) - amino group (-NH₂) adjacent amino acid monomers are held together by covalent peptide bonds

Question 41

Enantiomers

Answer 41

sterioisomers or mirror image isomers - same chemical properties but different physical properties racemases: enzymes capable of interconverting specific enantiomers

Question 42

Polypeptides

Answer 42

series of amino acid sequences joined together by peptide bonds (each polypeptide has an amino end and a carboxyl end) \*a polypeptide could be a whole protein or just a subunit of a larger protein -a protein is a functional unit

Question 43

Secondary structure and Tertiary structure

Answer 43

Secondary: folds or twists in parts of polypeptide that form a more stable structure (bond between amino group H and carboxyl group O) Tertiary: held together by - hydrogen bonds - electrostatic interactions - hydrophobic interactions with water - covalent bonds between -SH groups from two different amino acids (disulfide bonds)

Question 44

Denaturation

Answer 44

unfolding of polypeptide chains due to: - extremes of pH - high temperatures - certain chemicals