MICRO UNIT 2 EXAM:

What is metabolism?

the buildup and breakdown of nutrients within a cell

What is catabolism?

breaking down complex molecules, aka taking large molecules and making them smaller

What is anabolism?

taking smaller molecules as building blocks to create bigger ones

What is collision therapy?

states that chemical reactions occur when atoms, ions, and molecules collide

What is activation energy?

the energy required for a chemical reaction to occur

What is the active site?

a region on an enzyme where substrates bind and undergo a chemical reaction. It plays a crucial role in catalyzing the conversion of substrates into products.

What is a substrate?

lower activation energy

What is a catalyst?

speed up chemical reactions without being altered

What is cofactor?

nonprotein components

What is a coenzyme?

organic cofactor

What are some factors that affect enzymes?

temp, pH, substrate concentration, inhibitors

What are competitive inhibitions?

fill the active site of an enzyme and compete w/ substrate

What are noncompetitive inhibitions?

the inhibitor is not competing for the active site, binds to the allosteric site

What is the main difference between fermentation and respiration?

fermentation is no oxygen, while respiration has oxygen and goes through the Krebs cycle

What is beta oxidation?

breaking down fatty acids into acetyl groups for energy

deamination?

Removal of amino group from amino acids during protein breakdown.

What is a light dependent reaction?

conversion of light energy into chemical energy (ATP /NADPH)

What is a light-independent reaction?

ATP and NADPH are used to reduce CO2 to sugar (carbon fixation) via the Calvin-Benson cycle

When photosystem I and II are both present, which one occurs first?

Photosystem 2

Understand how the physical requirements of temperature, pH and osmotic pressure affect growth:

Temperature influences enzyme activity, pH affects protein structure, and osmotic pressure impacts water balance.

Understand how the chemical requirement of oxygen affects growth

Without oxygen, cells cannot efficiently produce energy, leading to impaired growth and metabolism in organisms.

What are psychrophiles?

Organisms that thrive in cold temperatures below 20°C. (cold-loving)

What are mesophiles?

Organisms that grow best in moderate temperatures around 20-45°C. (moderate-temp loving)

What are thermophiles?

Organisms that flourish in high temperatures above 45°C. (heat-loving)

What are acidophiles?

thrive in acidic environments (pH < 3)

What are neutrophiles?

grow best in neutral pH environments (pH 5-8)

What are alkaliphiles?

prefer alkaline conditions/ high pH environments (pH > 9)

What is a halophile?

an organism that thrives in high salt concentrations, typically found in environments like salt lakes or salt mines.

What is an aerobe?

Organisms that require oxygen for growth.

What is an anaerobe?

Organisms that can survive without oxygen.

What is a facultative anaerobe?

Organisms that can switch between aerobic and anaerobic metabolism. (can survive with or without oxygen)

Which type of lab handles the deadliest microbes like Ebola and smallpox?

Biosafety Level 4 (BSL-4) labs

What is the selective medium?

Promotes the growth of specific organisms while inhibiting others

What is the differential medium?

Allows distinguishing between different types of organisms based on their growth characteristics

What is the enrichment medium?

Stimulates the growth of specific organisms by providing specific nutrients.

How do most bacteria reproduce?

through binary fission, a process where a single cell divides into two identical daughter cells.

What is direct count?

Counting cells using a microscope.

What is Serial Dilution and Plate Count?

Diluting samples to count viable cells. (most used method)

What is MPN?

Most Probable Number method for estimating cell concentration.

What is filtration?

Filtering samples to concentrate cells.

What is turbidity?

Measuring cloudiness to estimate cell density.

destroys harmful microorganisms (only used on inanimate objects)

What is a disinfectant?

What is an antiseptic?

destroys harmful microorganisms on living tissue (rubbing alcohol, iodine, hydrogen peroxide)

What is a bacteriocidal chemical?

kills bacteria

What is a bacteriostatic chemical?

only inhibits bacteria, does not kill it

Which of the following works better for killing microbes: moist heat or dry heat?

moist heat

What are some alternatives to reducing microbes in heat sensitive materials?

pasteurization or filtration

What is pasteurization?

reduces spoilage organisms and pathogens

What is filter sterilization?

Removes microbes by passing through a filter.

What is refrigeration and feezing?

Slows microbial growth by lowering temperature.

What is lyophilization?

freeze drying to preserve microbes

What is Desiccation?

Drying out microbes to inhibit growth.

What is osmotic pressure?

using high salt/sugar to dehydrate microbes

What is UV radiation?

Damages microbial DNA to prevent reproduction.

Why is phenol important?

due to its use in the production of various chemicals, disinfectants, and pharmaceuticals. It is also used in the synthesis of plastics, resins, and as an antiseptic in medicine.

What is a halogen?

• column 7 of the periodic table

• group of non-metal elements in the periodic table (fluorine, chlorine, bromine, iodine, and astatine. They have seven electrons in their outer shell, making them highly reactive.

What is a heavy metal?

has a heavy atomic mass, toxic to humans (mercury and lead)

What is a tincture?

solution in aqueous alcohol

What makes alcohol a little unusual as an antiseptic?

because of it being a drying agent

What type of chemical is hydrogen peroxide and what type of bacteria does it work well against?

• Chemical Type: Hydrogen peroxide is a chemical compound with the formula H2O2, classified as a peroxide.

• Bacteria: Hydrogen peroxide is effective against a wide range of bacteria, including Staphylococcus, Streptococcus, and E. coli

What is genetics?

the study of genes, how they carry information, how information is expressed, and how genes are replicated

What is a gene?

segments of DNA that encode functional products, usually proteins

What is a chromosome?

structures containing DNA that physically carry hereditary information; also contain genes

What is genotype?

Genetic makeup of an organism.

What is phenotype?

Observable traits of an organism influenced by genotype and environment

What are several differences between RNA and DNA?

• Structure = RNA is single-stranded, while DNA is double-stranded.

• Sugar = RNA contains ribose sugar, DNA contains deoxyribose sugar.

• Bases = RNA has uracil (U) as a base instead of thymine (T) found in DNA.

• Function = RNA is involved in protein synthesis, DNA stores genetic information.

• Location = RNA is found in the cytoplasm and nucleus, DNA is mainly in the nucleus.

Understand what is meant when we say polymerases and ribosomes work in a 5’ to 3’ direction:

refers to the direction in which they synthesize nucleic acids. They add nucleotides to the 3’ end of the growing strand, moving towards the 5’ end.

What is the process of transcription?

the process of copying DNA into mRNA

What is the process of translation?

converting mRNA into proteins

What is the process of replication?

duplicating DNA.

Understand the basics of a replication fork:

a structure formed during DNA replication where the DNA double helix is unwound and new DNA strands are synthesized. It involves the leading and lagging strands, DNA polymerase, primase, helicase, and other enzymes.

What is a leading strand?

synthesized continuously in the 5' to 3' direction

What is a lagging strand?

synthesized discontinuously in Okazaki fragments.

What are Okazaki fragments?

short, newly synthesized DNA fragments formed on the lagging strand during DNA replication. They are created discontinuously and later joined together by DNA ligase to form a complete strand.

When are RNA primers needed?

RNA primers are needed in DNA replication to provide a starting point for DNA polymerase to begin synthesis. They are essential for initiating the replication process

Know how to read the genetic code or codon chart:

To read the genetic code or codon chart, start from the middle of the chart and match the mRNA codon to the corresponding amino acid. The chart shows all possible combinations of three nucleotides (codons) and their corresponding amino acids.

What is mRNA (messenagr RNA)?

Carries genetic information from DNA to ribosomes for protein synthesis.

What is rRNA (ribosomal RNA)?

Forms the structure of ribosomes and helps in protein synthesis.

What is tRNA (transfer RNA)?

Transfers amino acids to the ribosome during protein synthesis.

What are condons?

sequences of three nucleotides on mRNA that code for specific amino acids during protein synthesis

What are anticondons?

complementary sequences on tRNA that bind to codons to ensure the correct amino acid is added to the growing polypeptide chain.

What is a polysome / polyribosome?

a cluster of ribosomes translating the same mRNA simultaneously, creating multiple copies of a protein. This process enhances efficiency in protein synthesis.

What is a mutation?

a change in the DNA sequence of an organism. It can lead to variations in traits and can be caused by various factors like radiation or errors in DNA replication.

What is transformation?

DNA uptake by bacteria from the environment.

What is transduction?

DNA transfer via bacteriophages.

What is conjugation?

DNA transfer through direct cell-to-cell contact.

Energy is stored long-term in the bonds ____ and used short-term to perform work from an _____?

glucose;ATP

What condition has the least effect on enzymatic activity?

cooler temperature

What is a characteristic of a competitive inhibitor of an enzyme?

binds to the active site of the enzyme that does not lead to the shape change of the active site

Which of the following products is made during Embden-Meherhof glycolysis?

pyruvate

Which of the following methods would be used to measure the concentration of bacterial contamination in processed peanut butter?

viable plate count

How many ATP are generated from the electron transport system per one glucose molecule? (in a prokaryotic cell)

34

Which method would be the most useful in quantitating sewage contamination in a local river?

most probable number count

An inoculated thioglycolate medium culture tube shows dense growth at the surface and turbidity throughout the rest of the tube. What is your conclusion?

the organisms are facultative anaerobes

A soup container was forgotten in the refrigerator and shows contamination. The contaminants are probably which of the following?

psychrotrophs

Which type of medium will help identify certain types of bacteria based on the colors they produce as they grow on the medium?

differential

Which of the following types of medical items requires sterilization?

needles

What is the method of control that sterilizes by using moist heat along with high pressure?

autoclaving

Which of the following chemical food preservatives is used in the wine industry but may cause asthmatic reactions in some individuals?

sulfites

Which chemical control of bacteria does not actually kill the bacteria and is only bacteriostatic?

freezing