Lecture 1 exam

What is a microorganism? What are some examples?

A living thing ordinarily too small to be seen without magnification; an organism of microscopic size

EXAMPLES:

* bacteria
* archaea
* protozoa
* fungi
* helminths
* viruses
* algae

What are the characteristics of bacteria?

* prokaryotic (has no nucleus)
* cell wall: peptidoglycan
* heterotroph and autotroph
* unicellular
* asexual (reproduces by binary fission)
* circular DNA

What are the characteristics of archaea?

* prokaryotic
* cell wall: pseudomurein (protien+sugar)
* cell wall lacks peptidoglycan
* heterotroph
* unicellular
* asexual

What are the characteristics of fungi?

* eukaryotic
* cell wall: chitin
* Heterotroph
* unicellular and multicellular
* asexual and sexual reproduction

What are the characteristics of protozoan?

* eukaryotic
* lacks cell wall
* heterotroph
* unicellular
* asexual and sexual reproduction
* linear DNA

What are the characteristics of algae?

* eukaryotic
* cell wall: cellulose
* autotroph (photosynthetic)
* unicellular and multicellular
* asexual and sexual reproduction

What are the characteristics of helminths?

* eukaryotic
* no cell wall
* heterotroph
* multicellular
* asexual and sexual reproduction

what makes viruses different from other microorganisms?

viruses are different from other microorganisms because they are acellular (not made of cells; non-living)

what is the structure of viruses?

what are helminths?

flat worms and round worms

What does it mean to say that a microbe is ubiquitous?

A microbe is ubiquitous means microbes are found everywhere

define genetic engineering

manipulates the genetics of microbes, plants, and animals for the purpose of creating new products and genetically modified organisms (GMO)

define recombinant DNA technology

Makes it possible to transfer genetic material from one organism to another and deliberately alter DNA

define bioremediation

Uses microbes already present or introduced intentionally to restore stability or clean up toxic pollutants

what is the term used to describe a disease-causing microorganism?

pathogen

What is the leading cause of infectious death in the US?

influenza and pneumonia

What is the leading cause of infectious death in the world?

lower respiratory infection

define taxonomy

the science of classifying living things

define nomenclature

the assignment of scientific names to the various taxonomic categories and to individual organisms

define classification

the orderly arrangement of organisms into a hierarchy

define identification

the process of discovering and recording traits of organisms so they can be placed in an overall taxonomic scheme

Who developed the formal system for classifying and naming organisms?

Carolus Linnaeus

Each organism has two names. The first name is the ________________ and the second name is the
_______________________.

genus; specific epithet (species)

How are the names of organisms written (i.e. what part of the name is capitalized, etc)?

* The genus is capitalized and species is lower case
* Both names are underlined (separately) or italicized, if typed

Carl Woese proposed that organisms may be classified into one of three different domains by analysis of their _____________.

rRNA

What are the three domains proposed by Carl Woese?

1. bacteria
2. archaea
3. eukarya

How are organisms classified and organized into several descending ranks, beginning with the most
general and ending with the smallest and most specific?

* Domain


* Kingdom
* Phylum or division
* Class
* Order
* Family
* Genus
* Species

Who was the first to report that living things were composed of little boxes or “cells” from looking at cork?

Robert Hooke

Who was the first to look at living microorganisms with a microscope?

Anton van Leeuwenhoek

Compare spontaneous generation and biogenesis.

\

\-Spontaneous generation is the hypothesis that living organisms arise from non-living matter; a "vital force" forms life while biogenesis is the living organisms arise from preexisting life

\

Describe the experiments performed by Redi. For each experiment, describe if the experiment was in support of spontaneous generation or biogenesis.

Francesco Redi made an experiment to test" maggots don't arise from decaying meat". He sealed a jar with decaying meat and a open jar with decaying meat. The sealed jar resulted in no maggots while the open jar resulted in formed maggots. An antagonist was that fresh air is required. A second experiment was done using netting and resulted in no maggots. This experiment is in support of biogenesis.

Describe the experiments performed by Needham. For each experiment, describe if the experiment was in support of spontaneous generation or biogenesis.

John Needham did an experiment testing "boiled nutrient broth and then covered the flasks after. He boiled broth a covered it which resulted in bacteria growing. The microbes came from air before he sealed it. This experiment is in support of spontaneous generation.

Describe the experiments performed by Spallanzani. For each experiment, describe if the experiment was in support of spontaneous generation or biogenesis.

Lazzaro Spallanzani did a similar experiment to Needham and tested “covering before boiling (microbes from air)”,so he covered broth then boiled. An antagonist is that the boiling destroyed vital force. This experiment is in support of biogenesis

Describe the experiments performed by Pasteur. For each experiment, describe if the experiment was in support of spontaneous generation or biogenesis.

Louis Pasteur did an experiment on results of s-shaped flask. He placed nutrient broth in an S-shaped flask, heated, not sealed. The results showed no growth. This experiment is in support of biogenesis.

What is pasteurization?

the application of a gentle heat for a short time

What are Koch’s postulates used for?

used to establish whether or not an organism is pathogenic and which disease it caused

What are the steps for Koch’s postulates?

1. The same pathogen must be present in every case of the disease.
2. The pathogen must be isolated from the diseased host and grown in pure culture
3. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal
4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism

How did Jenner produce the 1st vaccine?

Exposed individual to material from cowpox lesion, Then exposed to smallpox, no infection

What type of enzymes were discovered in the 1970s that is used to cut DNA in specific ways?

restriction enzymes

What technique was invented in the 1980s by Kary Mullis, that was awarded the Nobel Prize in 1993,
that is used to amplify and subsequently analyze DNA?

polymerase chain reaction (PCR)

What is the term for anything that has mass and takes up space?

matter

Know the parts of the atom (i.e. the protons, neutrons, and electrons). Name which parts are positively charged, negatively charged, and neutral.

* protons are positively charged
* electrons are negatively charged

Which parts are in the nucleus of the atom?

protons and neutrons

Which part of the atom is involved in chemical bonding?

electrons

What are elements?

any substance that cannot be reduced to any simpler set of constituent substances through chemical means

What defines an element?

the number of protons in its nucleus

Fluorine has 9 protons, 9 neutrons, and 9 electrons. What is fluorine’s atomic number? What is
fluorine’s mass number?

atomic number = 9

mass number = 18

What are isotopes?

have the same numbers of protons and electrons but different numbers of neutrons

What is it about carbon-12, carbon-13, and carbon-14 that makes them all carbon?

all have 6 protons

What is different between carbon-14 and carbon-12?

carbon-14 has mass number of 14 and 8 neutrons

carbon-12 has mass number of 12 and 6 neutrons

How many electrons are in the first electron shell? How many electrons are in second electron shell?
How many in the third?

1st shell: 2 electrons

2nd shell: 8 electrons

3rd shell: 8 electrons

When is an atom stable?

Chemical bonding comes about as atoms “seek” their lowest energy state (when they are the most stable). An atom achieves this state when it has a filled outer electron shell

What are ions?

How do you know if an atom is an ion (i.e. what is different in the atom)?

List and describe the three types of chemical bonds.

1. Covalent bond: atoms share one or more electrons
2. Ionic bond: atoms lose and accept electrons from each other
3. Hydrogen bond: a covalently linked hydrogen atom can react with an electronegative atom (like oxygen)

What is a compound?

a substance consisting of two or more different elements combined in a fixed ratio

what is a molecule?

formed when 2 or more atoms are held together by covalent bonds

Is a NH3 molecule polar or non-polar? How do you know? How about a CH4 molecule?

Why does sodium and chloride form a bond?

Sodium is a metal, and chloride is a poisonous gas. However, when chemically combined, an edible compound emerges

* sodium transfers electron to chloride so they both can have full outer shells

What atoms do organic molecules always contain?

carbon and hydrogen

What atom do inorganic molecules usually lack?

carbon

Why is water considered to be polar? In hydrogen bonding, what will the hydrogen of one water
molecule bond with?

What property of water allows water to be transported up a plant from the roots to the leaves?

Water has a great capacity to absorb and retain heat. Because of this, we say that water has a high _________________________.

specific heat

What property of water allows life to live in water even when the water freezes in colder climate?

define solution

A completely homogenous mixture made of two or more substances

define solute

The substance that is dissolved

define solvent

The substance in which something is dissolved; The dissolving agent

When you add salt to water and the salt dissolves, what is
the salt called?

the salt is a solute

What makes a compound hydrophobic or hydrophilic?

**Hydrophilic substances**:

* Substances that have an affinity to water
* ==*Substances that can H-bond with water*==
* Ionic compounds: salts
* Polar molecules: sucrose (table sugar)

**Hydrophobic substances**:

* Substances that are excluded (repelled) by water
* ==*Substances that can’t H-bond with water*==
* Nonpolar, non-ionic: vegetable oil

What is an acid? What is an example?

Substances that release H+ in solution and increase H+ concentration (pH < 7)

EX: HCl

what is a base? What is an example ?

Substances that release OH− in solution and decrease H+ concentration (pH > 7)

EX: NaOH

If an acid is added to water, will the pH of the solution increase or decrease? Why?

If a base is added to water, will the pH of the solution increase or decrease? Also, what happens to the
hydroxide ion concentration as a result of a base being added?

What is a buffer? How does it work (i.e. what happens when H+ is depleted or in excess)?

**Buffers**: resist change in pH of a solution

* Donate H+ when depleted
* Accept H+ when in excess

Why is carbon central to life (i.e. what is it about its structure that makes it important)?

LINKAGE

* Carbon has great bonding capacity due to its structure.
* Carbon’s outer shell has only four of the eight electrons necessary for maximum stability in most elements.
* Carbon atoms are thus able to form stable, covalent bonds with a wide variety of atoms, including other carbon atoms

What are functional groups and why are they important?

functional group: a group of atoms that confer a special property on a carbon-based molecule

* affects a biological molecule’s function in a characteristic way.

What are the four classes of macromolecules? List the necessary atoms that must be present within
each of them.

1. proteins
2. carbohydrates
3. nucleic acid
4. lipids

What type of reaction takes place when monomers are linked together to form polymers?

What happens in the reaction?

dehydration reaction

* Attaches monomer to growing chain
* Results in the loss of 1 water molecule

What type of reaction takes place when polymers are broken down?

What happens in the reaction?

Hydrolysis reactions

* Breaks one monomer off the end of the polymer
* Requires 1 water molecule

What is the monomer of carbohydrates?

monosaccharide

what is the polymer of carbohydrates?

polysaccharide

What is the monomer of proteins?

amino acid

what is the polymer of proteins?

polypeptide or protein

What is the monomer of nucleic acids?

nucleotide

what is the polymer of nucleic acids?

nucleic acid

What are the four complex carbohydrates that are important for life? What is the function for each?

* **starch**: nutrient storage form of carbohydrates in plants
* **glycogen**: the nutrient storage form of carbohydrates in animals
* **cellulose**: a rigid, structural carbohydrate found in the cells walls of many organisms; major source of insoluble fiber, which helps move foods through the digestive tract
* **chitin**: a tough carbohydrate that forms the external skeleton of arthropods

What is the structure of a fat? Is a fatty acid polar or non-polar? Why?

What is the difference between saturated and unsaturated fats?

Fats made of **saturated fatty acids**

* All carbon-carbon bonds are single bonds
* The molecule is “saturated” with hydrogens
* Straight linear molecules (no kinks or bends)

Fats made of **unsaturated fatty acids**

* Have at least one carbon-carbon double bond
* The molecule is NOT “saturated” with hydrogens
* Double bond forces a kink in the molecule

Which is more likely to be solid at room temperature, saturated or unsaturated fats? Why?

Saturated fats are solid at room temperature because molecules easily stack together into a solid

What class of macromolecules do steroids belong to? What class of macromolecules do phospholipids
belong to?

lipids

Describe how phospholipids orient themselves to form cell membranes (i.e. what part of the
phospholipid interacts with the inside of the cell, etc.).

One end is polar and can interact with water

* Phosphate head

Other end is nonpolar and can interact with other fats

* Fatty acid tails

What is different between one amino acid and another? In other words, which part of the amino acid is variable?

Describe the four levels of structure of proteins.

1. **Primary**: The linear sequence of amino acids in the polypeptide
2. **Secondary**: Coiling and pleating of chain held by hydrogen bonds
3. **Tertiary**: irregular folding due to bonding between the R-groups of AA’s in the polypeptide chain
4. **Quaternary**: Interactions between 2 or more polypeptide chains (these type of proteins are oligomers)

Why is a fever so bad for our body?

proteins in our body denature above 104°F

Which monomer is composed of a sugar, phosphate group, and a nitrogenous base?

nucleic acids

Compare and contrast DNA and RNA

similarities:

* cytosine, guanine, adenine
* phosphate group
* phosphodiester linkage

differences:

* DNA has thymine, deoxyribose (missing O at c2), 2 stands
* RNA has uracil, ribose (has O at c2), 1 strand