LEC EXAM 2 REVIEW

Last Common Ancestor

Evidence suggests that all eukaryotes come from one common ancestor due to similar genetic makeup.

Cilia and Flagella

Eukaryotic flagella are 10x thicker than bacterial flagella and eukaryotic cillia are found in certain protozoa and animal cells.

Glycocalyx

A waxy protective coating made of polysaccharides that contributes to protection, adherence, and signal reception.

Appears as

• a network of fibers

• a slime layer

• a capsule

Phospholipid Bilayer

A bilayer consisting of polar heads and fatty acid tails that forms cell membranes.

Nucleus

The most prominent organelle in a cell, separated by a nuclear envelope with small pores for macromolecule transport within a lipid bilayer

Endoplasmic Reticulum (E.R.)

Organelles for transport and storage; rough E.R. has ribosomes and transports materials, while smooth E.R. synthesizes lipids.

Golgi Apparatus

Organized for transport and modifying materials from the E.R. to the cell wall/membrane.

Mitochondria

Organelles that produce ATP by extracting chemical energy from nutrients.

Chloroplasts

Organelles found in algae and plant cells that convert sunlight into chemical energy via photosynthesis.

Ribosome (80s)

Composed of subunits 40s and 60s, responsible for protein synthesis.

Cytoskeleton

A structure that holds organelles in place, maintains cell shape, and assists in the movement of RNA and vesicles.

Endosymbiosis

The theory that larger cells engulfed smaller cells, leading to a symbiotic relationship.

Yeast vs. Hyphae

Yeast are round/oval and reproduce asexually with a soft uniform texture, while hyphae are long/threadlike cells found in filamentous fungi with a cottony/hairy or velvety texture.

Heterotropic Nutrition

Acquiring nutrients from a variety of organic substrates.

Saprobic Nutrition

Acquisition of nutrients from dead organic matter in soil or aquatic habitats.

Parasitic Nutrition

Nutrient acquisition from living hosts often requires a living host. They penetrate substrate and secrete enzymes that reduce it to small molecules that can be absorbed by the cells. Often found nutritionally poor environments (high salt or sugar)

Trophozoite

The active, feeding stage of protozoa.

Protozoan Life Cycle

Trophozoite -> Cyst due to nutrient lack -> Cyst hatching back to Trophozoite with restored nutrients.

Flatworm vs. Roundworm

Flatworms have a thin, segmented body, while roundworms are elongated and unsegmented.

Filterable Virus

Pathogenic solution passes through a porcelain filter remains pathogenic, indicating a pathogen smaller than bacteria.

Properties of Viruses

• parasitic

• possess a basic structure of capsid and nucleic acid

• take over host genetic material and regulate synthesis to assemble new viruses

• appenages attach to host

• lack enzymes and machinery for most metabolic processes and synthesizing proteins

• 10x smaller than bacteria

Bacteriophage

Viruses that infect bacteria, usually containing DNA.

Lytic Cycle

• phage attaches to host cell and infects cell with DNA

• DNA from the phage replicates and makes proteins

• new phage particles are created and released from cell

Lysogenic Cycle

• Phage infects cell and becomes integrated into host DNA

• cell divides along with mix of DNA (from phage and original cell)

• DNA from the phage replicates and makes proteins 

• new phage particles are created and released from cell

Prions

Infectious agents composed of protein that cause brain tissue damage.

Essential Nutrients

Substances that must be provided to organisms to support growth.

Macronutrients

Nutrients required in large quantities, such as carbon (C), hydrogen (H), oxygen (O).

Diffusion

Movement of molecules from an area of higher concentration to lower concentration.

Osmosis

Diffusion of water across a selectively permeable membrane.

Facilitated Diffusion

Transport of molecules across a membrane via protein channels without energy expenditure.

Active Transport

Energy-requiring process to move substances against a concentration gradient.

Aerobes

Organisms that require oxygen to survive. (most fungi, protozoa, bacteria)

Anaerobes

Organisms that die in the presence of oxygen. (most intestinal bacteria)

Mutualism

A relationship where both organisms benefit from living together.

Binary Fission

• one cell becomes two

• parent cell enlarges

• duplicated its chromosomes

• starts to pull its cell envelope together to the center of the cell

• cell wall evetnually forms a complete septum

Metabolism

All chemical reactions and physical workings of a cell.

Catabolism

Processes that break down bonds of larger molecules, releasing energy.

Anabolism

Processes that synthesize larger macromolecules from smaller ones, requiring energy.

Enzymes

• serve as a physical site upon which substrate can be positioned for various reactions

• larger in size than substrate

• presents in unique active site matched to a particular substrate

• binds to substrate

• participates directly changes to the substance

• does not become part of the products

• not used up by the reaction

• can function over and over again

Competitive Inhibition

Inhibition where multiple substrates fight for the enzyme's active site. Only the correct substrate produced a product.

Non-competitive Inhibition

Inhibition where a molecule binds elsewhere on the enzyme, changing its shape, blocking a reaction from occurring

Amphibolism

The integration of catabolic and anabolic pathways to improve cellular efficiency.

Regulation of Enzyme Action

Changes in normal conditions that can cause enzymes to be unstable, distort, or denatured, which prevent substrate from attaching to the active site (temp, pH, osmotic pressure)

Enzyme Naming

Classified and named according to characteristics (site of action, type of action, substrate)

end in -ase

Holoenzyme

a combination of protein and one or more cofactor

Apoenzyme

protein portion of a holoenzyme

Cofactors

 either organic molecules called coenzymes or inorganic elements (metal ions)

Tubidity

Greated turbidity, larger population size of microbes

Parasitism

A relationship in which the host organism provides the parasitic microbe with nutrients and a habitat, host suffers from the relationship

Commensalism

The partner called the commensal received benefits while its partner is neither harmed nor benefited

Halophiles

Prefer higher concentrations of salt

Aerotolerant Anaerobes

Don't need oxygen but wont die if exposed to small amounts of oxygen - think streptococci bacteria

Facultative Microbes

Don't care about oxygen (could take it or leave it) - think some gram -negative intestinal bacteria

Microaerophiles

Need small amounts of oxygen (but full amounts will harm it)  - think soil microbes 

Minimum Temperature

Lowest temperature that permits a microbes continued growth and metabolism

Maximum Temperature

Highest temp at which growth and metabolism can proceed before proteins are denatured

Optimum Temperature

An intermediate between the min and max that promotes the fastest rate of growth and metabolism

Endocytosis

Cell incloses the substance in its membrane. Simultaneously forms a vacuole and engulfs a substance

ZInc (Zn)

Essential regulatory element for eukaryotic genetics

Iron (Fe)

Important component of cytochrome proteins of cell respiration

Magnesium (Mg)

Component of chlorophyll and stabilizer of membranes and ribosomes

Calcium (Ca)

Stabilizer of cell wall and endospores of bacteria

Sodium (Na)

Important for certain types of cell transport

Potassium (K)

Essential to protein synthesis and membrane function

Carbon

Makes up all your macromolecules (building blocks) of life - proteins, carbohydrates, lipids and nucleic acids

Hydrogen

Important for hydrogen bonds, source of free energy in cell respiration (NAD --> NADH) , maintains pH

Oxygen

Major component in all macromolecules! structural and enzymatic function. Aerobic cell respiration stops without it!

Nitrogen

Major component in Proteins, DNA, RNA, and ATP.  synthesizes amino acids, amphibolism

Phosphate

ATP (cellular energy transfers)!!! Nucleic Acid backbone (essential for genetics)

Sulfur

Disulfide Bonds (protein structure and shape), essential component to some vitamins

Chemotroph

Microbe that gets its energy from chemical compounds

Phototroph

Microbe that photosynthesizes

Lithoautotroph

Rely totally on inorganic minerals and require neither sunlight or organic nutrients

Chemoorganic Autotrophs

Use organic compounds for energy and inorganic compounds as a carbon source

Chemoautotrophs

• Chemoorganic autotrophs

• Lithoautotrophs

photoautotroph

Uses CO2 that can be used by themselves and by heterotrophs

Autotroph

• An organism that uses inorganic CO2 as its carbon source

• Can convert CO2 into organic compounds

• Not nutritionally dependent on other living things

Obligate Parasites

Unable to grow outside of a living host

Intracellular Parasites

Live within cells 

Endoparasites

Live in the organs and tissues

Ectoparasites

Live on the body

Pathogens

Cause damage to tissues or even death

Parasites

Derive nutrients from the cells or tissues of a living hosts, range from viruses to helminths

Saprobes

Free-living organisms that feed on organic detritus from dead organisms, decomposers, recycle organic nutrient

Chemohetrotrophs

Derive both carbon and energy from organic compounds, process these molecules through cell respiration or fermentation

Heterotroph

An organism that must obtain its carbon in an organic form

Micronutrient

Present in much smaller amount are involved in enzyme function and maintenance of protein structure (Mg, Zn, Ni)

Antibiotics and Viruses

• antibiotics have no effect on viruses (just bacterial infections)

• drugs damage both host cells and host cells 

• viruses disguise themselves using host cell membrane 

• easier to develop vaccines than to treat viral diseases

Connections to Chronic Infections

Type 1 diabetes, MS, various cancers, alzheimers, obesity

Infections with High Mortality Rates

rabies, AIDS, ebola

Prominent Viral Infections Worldwide

dengue fever, rift valley fever, yellow fever

Common Causes of Acute Infections

Colds, hepatitis, chickenpox, influenza, herpes, warts

In Vivo

Laboratory bred animals and embryotic tissues

In Vitro

cell/tissue culture methods

Oncogenic

• Cancer causing viruses

• Carry genes that directly cause cancer or they produce proteins that induce a loss of growth regulation leading to cancer

  • increase rate of growth

  • change in chromosomes

  • change in cells surface molecule

  • capacity to divide indefinitely 

• papillomaviruses, herpes virus, Hep B, HTLV-1

Sporangiospores

Cleavages with a saclike head (sporangium) and a stalk (sporangiophore)

Condiopsores

Free spores (no sac)

Capsid

• protein shell that protects nucleic acid

• most prominent feature of virus

• nucleocapsid (only on naked viruses)

Envelope

External covering over capsid (part of host cell membrane to go undetected)

Spikes

Project from the nucleocapsid or the envelope that allow viruses to dock with host cells