Biology (Princeton Review)

What are Proteins?

Biological molecules that act as enzymes, hormones, receptors, channel transporters, antibodies and support structures

What are Peptide Bonds?

The bond formed between the carboxyl group of one amino acid and the alpha amino group of another

What is a residue?

A single amino acid in the chain

What is Proteolysis?

The hydrolysis of a protein by another protein

What is Protease?

A proteolytic enzyme, a protein doing the cutting

What is a Disulfide bond?

A covalent Sulfur - Sulfur bond. Typically formed by 2 Cysteines

Disulfide bonds stabilize what kind of structure?

Tertiary protein structures

What is Denaturation?

The disruption of a proteins shape without breaking.

Primary Structure

Linear ordering of amino acids

Secondary Structure

Initial folding of a polypeptide chain

What is a alpha helix?

A coiled secondary structure

What is a Beta Parallel Sheet?

A secondary structure folding in the same direction

What is a Beta Anti-parallel Sheet?

A secondary structure folding in opposite direction

What is a Tertiary Structure?

Interactions between amino acid side chains

How do Hydrophobic R-Groups fold?

They tend to fold into the interior of a protein

How do Hydrophilic R-Groups fold?

They tend to fold outward, being exposed to the water on the surface of a protein

What is a Quaternary structure?

Interactions between polypeptide subunits

What is a Subunit?

Single polypeptide chain that is apart of a large complex

What forces stabilize a quaternary structure?

Non-covalent, Van der Waals, H-Bonds, disulfide bonds and electrostatic interactions

What are Carbohydrates?

The principle energy source for cellular metabolism

What is a monosaccahride?

A single carbon molecule

What is a disaccharide?

Two monosaccharides bonded by a glycosidic linkages

What is a glycosidic linkage?

A covalent bond formed in a dehydration reaction

What is Glycogen?

Energy storage form of a carbohydrate in animals

What is Starch?

Energy storage form of carbohydrate in plants

What is Cellulose?

A chain of glucose forming the plant cell wall.

What are lipids?

Adipose cells that store energy

What are phospholipids?

Lipid molecule that forms a barrier between intra and extracellular environmemn’s

What is Cholesterol?

The building block for hydrophobic steroid hormones

What are hydrophilic lipids?

Polar substances that dissolve well in water

What is saturated fat?

Fatty acid chain consisting of single carbon carbon bonds only

What is unsaturated fat?

Fatty acid chain consisting of carbon carbon double bonds

What is a Hydrophobic Interaction?

The force driving hydrophobic tails into the center of the micelle

What is a Triacylglycerol?

A storage type of fat composed of 3 fatty acids bonded to a glycerol and used as an energy source

What is lipase?

The enzyme used to store fat

How are phospholipids stabilized?

Stabilized by Van der Waals forces between long tails

What increases membrane fluidity?

Unsaturation and longer tail length

How is phospholipid structure determined?

The degree of saturation, tail length and amount of cholesterol

What are Terpenes?

Build from isoprene units and is the functional unit of a terpenoid

What are Steroids?

Hydrophobic structures similar to cholesterol

What lipid is Testosterone and Estradiol made of?

Cholesterol

What are nucelotides?

The building block of nucleic acids

What does a nucleotide contain?

Ribose or Deoxyribose sugar, purine or pyrimidine and phosphate units

What is a virus?

An obligate intracellular parasite that relies on other organisms. They aren’t living

What is a virus’s genome made of?

DNA or RNA and is single or double stranded and can be linear or circular

What is a Bacteriophage?

A virus that infects bacteria

What is a capsid?

A protein coat surrounding a viral nucleic acid genome

How is a virus classified?

By the capsid

How does a virus infect an Animal cell?

They bind to a specific receptor on the cell surface and then is fused or by endocytosis

What is the lytic cycle?

The breakdown, replication, assembly and ruptures the host releasing the newly produced viruses

What is the lysogenic cycle?

The integration, replication, assembly of viruses but remains dormant

What is the productive cycle?

Like the lytic cycle but instead forms buds than rupture

What is a Provirus?

The dormant form of the viral genome in animal virus lysogenic cycle

What is (+)RNA Virus?

Single stranded viral RNA that serves as mRNA. Encodes RNA dependent RNA polymerase

What is (-) RNA Virus?

Complementary piece of RNA that encodes viral proteins and carries RNA Dependent RNA polymerase

What does a Retrovirus do?

Encodes reverse transcriptase. +RNA viruses that integrate into the host genome as proviruses 

What must Double Stranded DNA viruses do?

Encode enzymes required for dNTP synthesis and DNA replication

What are sub-viral particles?

Infections agents smaller and simpler than viruses

What are Prions?

Misfolded versions of a protein that already exist; they’re self replicating and have a long incubation period

What are Viroids?

Short pieces of circular, ssRNA that lack capsids and do not code for proteins

What is the Cell Theory?

1. All living organisms are composed of one or more cells and products

2. Cells are the monomer for any organism

3. New cells arise from pre-existing living cells

Do prokaryotes have membrane-bound organelles?

No they do not contain membrane bound organelles

What are the main types of Prokaryotes?

Bacteria, Archaea and Cyanobacteria (blue-green algae)

Describe the genetic material in prokaryotes

They have 1 double-stranded circular DNA chromosome genome NOT located in genome

How does transcription and translation differ in prokaryotes compared to eukaryotes?

In prokaryotes transcription and translation occur at the same time in the same location

When do ribosomes begin translating mRNA in prokaryotes?

Ribosomes begin to translate mRNA before its completely transcribed 

What is a plasmid in prokaryotes?

A circular piece of DNA smaller than a genome that encodes gene products and orchestrates conjugation

What surrounds bacterial cytoplasm?

A lipid bilayer and peptidoglycan 

What is the bacterial cell wall composed of?

Composed of peptidoglycan 

What is Gram-Positive Bacteria?

Thick peptidoglycan that stains purple

What is Gram-Negative Bacteria?

Thin peptidoglycan that stains pink and has 2 layers

What does Monotrichous mean?

Flagella that is at one of the cell

What does Amphitrichous mean?

Flagella that is on both sides of the cell

What does Peritrichous mean?

Flagella surrounds the cell

What is chemotaxis?

Bacteria that move toward attractors or away from toxins

What are chemoreceptors?

A signal that influences direction of flagellar rotation 

What is Pili?

Long projections that are used to adhere to different surfaces

What is a sex pilus on bacteria?

A pilus that attaches F & F + bacteria to form a conjugation bridge

What is a mesophile?

Bacteria that can survive moderate tem 30 C

What is a Thermophile?

Bacteria that survive high temp 100 C

What is a Psychrophilus?

Bacteria that can thrive in low temp 0 C

What are Chemoautotrophs?

Organism’s that that get energy from chemical and use CO2 for carbon source

What are Chemoheterotrophs?

Organism’s that use organic molecules for energy and carbon source

What are Photoautotrophs?

Organism’s that only use CO2 as carbon source and obtain energy from the sun

What are Photoheterotrophs?

Organisms that get energy from the sun but use organic molecules for energy source

What is an Auxotroph?

Bacteria that can’t survive on minimal medium, needs additional growth medium to grow

What are obligate aerobes?

Bacteria that needs oxygen to live

What are Facultative Anaerobe’s?

Bacteria that uses oxygen but do not need it. Able to ferment

What is a Tolerant Anaerobe?

Bacteria that can grow and live with or without oxygen. Able to ferment

What is an Obligate Anaerobe

Bacteria that will die in the presence of oxygen

What is Respiration?

Glucose catabolism with use of Oxygen

What is Fermentation?

Glucose catabolism without the use of oxygen

What is Binary Fission?

Bacteria replicate genome and then splits in two

What is the Log Phase of a bacterial life cycle?

The linear growth of bacteria

What is the Lag Phase of a bacterial life cycle?

Bacteria do not undergo cell division even if growth conditions are ideal

What is the Stationary phase of a bacterial life cycle?

Bacterial cells stop dividing due to lack of nutrients

What is the carrying capacity of a bacterial life cycle graph?

The maximum population produced at stationary phase

What are Endospores?

Growth formed in unfavorable growth conditions from gram-positive bacteria.

What is Germination in bacterial enospores?

The metabolic reactivation of endospores

What is Transduction in Bacterial Reproduction?

The transfer of DNA from one bacteria to another