Cell and Molecular Biology Lecture Notes Review

Flashcards covering key concepts from lecture notes on cell biology.

What are the three components of the modern Cell Theory?

All living things are composed of one or more cells; Cells are the basic structural and functional units of living things; All cells come from pre-existing cells.

Describe the structure and function of a mitochondrion.

Rod-like, double-membrane structure; inner membrane folded into CRISTAE; site of ATP production via Cellular Respiration.

What are centrioles and what is their role in the cell?

Paired cylindrical bodies composed of 9 triplets of microtubules; organize microtubule network for spindles and aster rays during mitosis; form bases of cilia and flagella.

Describe a vacuole and its function.

Bubble-like sac involved in the storage of cell materials, especially water

What is the cytoplasm and what does it do?

Jelly-like fluid which holds the cell organelles in place.

Describe the nucleolus and its main function.

Small dense body within the nucleus composed of ribosomal RNA and protein; site of ribosome production

What is the nuclear membrane and what is its function?

Double membrane structure with pores; protects the nucleus and controls the passage of materials into and out from the nucleus.

What is the nucleus and what is its function?

Spherical structure located near the middle of the cell which controls all cell activities.

Describe the Rough Endoplasmic Reticulum (RER) and its primary function.

Double membrane transport system extending from the nucleus to the cell membrane; transports materials throughout the cell.

Describe the Golgi Body and its function.

Stack of flattened smoothed membrane sacs and associated vesicles; packages, modifies, and separates proteins for release from the cell.

Describe microtubules and their function.

Long cylindrical structures made of tubulin protein; support the cell and gives it shape; also form centrioles.

What are ribosomes and what is their function?

Small particles which are the sites of protein Synthesis; may be free or attached to the rough endoplasmic reticulum.

Describe the Smooth Endoplasmic Reticulum (SER) and what it does.

Membranous system of sacs and tubules; site of lipid and steroid production and lipid metabolism.

Describe the cell membrane and its function.

Outer covering of an animal cell; consists of a double layer of phospholipids with protein embedded in it; controls the passage of materials into and out from the animal cell.

Briefly describe the process of cell fractionation.

Cells are placed in a cold, isotonic, buffered solution, then broken up to release organelles. The resultant fluid is then filtered to remove any complete cells and large pieces of debris.

Briefly describe the process of ultracentrifugation.

Fragments in the filtered liquid are separated in a centrifuge, spinning tubes of the liquid at very high speed, to create a centrifugal force.

What are the 4 major classes of biological molecules?

Carbohydrates, Lipids, Proteins, Nucleic acids

What are two functions of carbohydrates?

Energy metabolism and storage and Structural material.

What are the 4 major types of carbohydrates?

Monosaccharides, Disaccharides, Oligosaccharides, Polysaccharides

Define monosaccharides.

Single saccharide which serves as a basic structural unit of all carbohydrates

Define Disaccharides.

Double saccharide composed of two saccharide monomers bonded together

Define Oligosaccharides.

Few-saccharide chain composed of 3-10 saccharide monomers bonded together

Define polysaccharides.

Many-saccharide chain composed of more than 10 saccharide monomers bonded together

Define hydrolysis.

Splitting a large molecule into 2 smaller ones and water is ADDED to the split.

Define Dehydration synthesis.

Two molecules are united, and water is REMOVED from the site of union.

Define lipids.

Insoluble in water but soluble in organic solvents, excellent energy storage molecules.

What are three major groups of lipids?

Fats and Oils, Phospholipids, Steroids

What is the main difference between a fat and an oil?

A fat is solid at room temperature whereas an oil is liquid at room temperature. A fat is usually from an animal, while an oil is generally from a plant.

Define a Saturated Fat.

Fatty acid hydrocarbon chain contains ALL SINGLE BONDS and the maximum number of hydrogen atoms

Define a Monounsaturated Fat.

Fatty acid hydrocarbon chain contains ONE DOUBLE BOND and less than the maximum number of hydrogen atoms

Define a Polyunsaturated Fat.

Fatty acid hydrocarbon chain contains TWO OR MORE DOUBLE BONDS and less than the maximum number of hydrogen atoms.

Define Phospholipids.

Resemble a fat, but contain a PHOSPHATE GROUP INSTEAD OF ONE FATTY ACID in the structure.

Define Steroids.

Types of lipids with a 4-ring carbon core.

What is the active site?

The site where the substrate temporarily joins with the enzyme.

Explain the Induced-fit Model.

According to the Induced-fit Model, the active site of an enzyme is flexible. This flexible active site is inactive until the substrate INDUCES a change in the shape of the active site so that the substrate will then fit in the active site.

What are the 4 major factors which affect the rate of enzyme activity?

Temperature, pH, Substrate Concentration, Enzyme Concentration

What are enzyme inhibitors?

Molecules that interact in some way with the enzyme to prevent it from working in its normal manner.

What are the 2 types of Enzyme Inhibitors?

Non-Specific and Specific

What occurs during Competitive Inhibition?

Chemicals that resemble an enzyme’s normal substrate will compete with the substrate for the active site. This is usually reversible.

What occurs during Noncompetitive Inhibition?

The inhibitor does NOT enter the active site, but binds to another part of the enzyme called the ALLOSTERIC SITE. This causes the enzyme to change its shape AND alter its active site. This process is irreversible.

What is a nucleic acid?

Stores and transfers genetic information (therefore determines heredity) as well as controls protein production.

Describe a nucleotide.

Linear polymer of nucleotides, consisting of 3 parts: Pentose Sugar, Phosphate Group, Nitrogenous Base.

Define Purines.

Nitrogenous bases which have 2 rings and includes Adenine and Guanine.

Define Pyrimidines.

Nitrogenous bases which have 1 ring and includes Uracil, Cytosine, and Thymine.

What are the 2 important nucleic acids?

DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid)

What does DNA do?

Contains and transfers genetic information, largest of all biological molecules.

What does RNA do?

Involved in the production of proteins

What are 3 types of RNA that are cell?

Messenger RNA, Transfer RNA, and Ribosomal RNA

What is energy?

The ability to do work; can be converted from one form to another but cannot be created nor destroyed.

What are the two general classifications of energy?

Kinetic Energy and Potential Energy

What is kinetic energy?

Energy of motion, active state of energy, energy released.

What is potential energy?

Energy of position, inactive state of energy, energy stored.

What does the First Law of Thermodynamics state?

Energy can be CONVERTED from one form to another, but it CANNOT be created nor destroyed

What does the Second Law of Thermodynamics state?

Systems tend towards greater systems of DISORDER (because energy spreads out)

What is entropy?

The measure of the disorder (randomness) of a system.

Define a chemical reaction.

A change that produces one or more substances due to the making or breaking of chemical bonds.

Define Exothermic (Exergonic) Reaction.

Chemical reaction which RELEASES energy and proceeds spontaneously.

Define Endothermic (Endergonic) Reaction.

Chemical reaction which ABSORBS (REQUIRES) energy and does NOT proceed spontaneously.

Define Metabolism.

Sum total of all the chemical reactions that occur in a living cell or organism.

Define anabolic reactions.

The metabolic reactions which build larger molecules from smaller molecules or atoms.

Define catabolic reactions.

The metabolic reactions which break large molecules down into smaller molecules or atoms.

What are FOUR MAJOR TYPES OF BIOLOGICAL CHEMICAL REACTIONS?

Neutralization, Redox (Oxidation-Reduction), Hydrolysis, and Dehydration Synthesis

What is Cellular Respiration?

Process of converting the chemical energy stored in food into a metabolically USEFUL form of energy (ATP).

What two phases does Cellular respiration occur in?

Anaerobic Phase and Aerobic Phase

Describe the Anaerobic Phase of Cellular Respiration

Cellular respiration which occurs in the ABSENCE of OXYGEN; takes place in the cytoplasm (cytosol) of the cell.

Describe the Aerobic Phase of Cellular Respiration

Cellular respiration which occurs in the PRESENCE of OXYGEN; takes place in the mitochondrion of the cell.

What happens during Glycolysis?

The process which consist of a series of ten separate reactions, in which glucose molecule (a hexose sugar) is split into two pyruvate molecules (triose sugars)

What occurs during Alcoholic Fermentation

Organisms have a LIMITED SUPPLY of NAD, to ensure that these anaerobic organisms do not run out of NAD, these organisms perform ALCOHOLIC FERMENTATION.

What happens during Oxidative Decarboxylation?

Each pyruvate must be ACTIVELY TRANSPORTED across the mitochondrial membrane (requires an ATP molecule)

What occurs during Enzyme Concentration

In any reaction catalyzed by an enzyme, the number of enzyme molecules present is very much smaller than the number of substrate molecules.

What occurs during Kreb's Cycle (CITRIC ACID CYCLE)?

Series of chemical reactions that occurs after glycolysis that has the form of a repeating cycle.

What occurs during Electron transport chain (oxidative phosphorylation)?

Enzymes and coenzymes called the ELECTRON TRANSPORT CHAIN form ATP

What causes Lactic acid (LACTATE) fermentation

When OXYGEN is not being provided to the muscles.

What are the 2 the types of Plant Organs

(B) VEGETATIVE Organs and (A) SEXUAL REPRODUCTIVE Organs

What are the functions of a root?

ANCHOR the plant in the ground, ABSORB water and dissolved nutrients from the soil, and STORE extra sugars made during photosynthesis.

what type of system is a stem and its function?

VASCULAR SYSTEM -continuous tubular pathway from the roots, through the stem, to the leaves- transports water and dissolved minerals from the roots to the leaves (through the XYLEM) and food (mainly glucose) from the leaves to the roots (through the PHLOEM).

what are the leaves functions?

ABSORB LIGHT ENERGY and PRODUCE GLUCOSE through the process of PHOTOSYNTHESIS.

What is a list of parts of a leaft?

Cuticle, guard cells, stomata, upper epidermis, palisade mesophyll, spongy mesophyll and lower epidermi

what does Photosynthesis do?

Photosynthesis is the process in which green plants capture the sun’s energy and convert this energy into chemical energy and stored within the bonds of carbohydrates (most notably GLUCOSE).

What are the Stages of Photosynthesis?

LIGHT (LIGHT-DEPENDENT) Reactions and DARK (LIGHT-INDEPENDENT) Reactions (Also called the Calvin Cycle)

What happens during the Light Dependent Reaction?

Occur in the THYLAKOID MEMBRANE of the chloroplast. The light reactions REQUIRE LIGHT ENERGY and H2O. The end products of the light reactions are ATP, NADPH, and O2.

What is required during the Light Independent Reaction?

The light reactions do REQUIRE CHEMICAL ENERGY IN THE FORM OF ATP and NADPH (produced during the light reactions) as well as CO2.

what does Photosynthesis uses from the electromagnetic spectrum?

VISIBLE (WHITE) LIGHT portion of the electromagnetic spectrum

What is a Pigment in the leaft and color light?

Molecule which differentially absorbs and reflects various wavelengths (colours) of light

Of all the pigments found within the chloroplasts of leaves, which is most important?

Chlorophyll a is the most important!

What does bacteria clustered in the bands mean???

red and blue light, support photosynthesis most effectively

what do Pigments (located in the thylakoid membrane) are ARRANGED for?

Groups which consist of several chlorophyll a, chlorophyll b, and carotenoid pigments

What does Photosystem consists of?

Chlorophyll a, Antennae Pigments,Electron Carriers

Does the Light or Dark Dependent Photosynthesis begins first???

When light enters a leaf, the light reactions of photosynthesis begin immediately. As a result of this first stage of photosynthesis, light energy is converted into chemical energy (stored as ATP and NADPH)

What does DNA is said to be denatured mean??

Two strands separate under the influence of heat

What where two Types of Pneumonia that Griffith used in in the experiment?

Two Types of Pneumonia: 1. Type S, which is virulent, has “encapsulated and 2. Type R, which is harmless or Avirulent, and has "non-encapsulated".

what Bacteriophage T2 is made of protein.

Head of the bacteriophage T2 is made of protein, but it contains DNA

What is dna replication about?

Each new DNA molecule contains one original (old) strand and one new strand.

What are the two different isotopes of nitrogen?

Two strains containing nitrogen: 14N (the more common isotope) and 15N (a heavier isotope)

Prokaryotic and Eukaryotic: what one contain contain circular DNA and what one contain, linear DNA.

Prokaryotes contain circular DNA and eukaryotes contain, linear DNA

How does DNA work?

DNA helicase unwinds and separates the parental double-helical DNA by breaking the hydrogen bonds

What strand of DNA contains one RNA Primer and which has many?

One the leading strand and MANY on the legging strand

How is is protein synthesis form?

All the structural and functional materials of a cell are made partially or entirely of proteins. It is generally agreed that each gene (composed of DNA) is responsible for the production of these proteins

What are the 2 stages of protein synthesis?

Transcription and Translation

What what is TRANSCRIPTION about??

the transferring of the DNA’s nitrogen base code to a mRNA molecule