Cells and Organelles and Bioenergetics and Enzymes and Macromolecyles

Cells are defined as the basic unit of _____.

Biology

What three characteristics define the 'dynamic' nature of cells?

The capacity to grow, reproduce, and become specialized.

Historically, what two factors limited early observations of cells?

Microscope resolution and lack of explanation for what was seen.

According to the cell theory, all organisms consist of _____.

One or more cells.

The cell theory states that the cell is the basic unit of _____ for all organisms.

Structure

Where do all cells originate from according to the cell theory?

Preexisting cells.

Modern cell biology is the result of the intersection of which three disciplines?

Cytology, Biochemistry, and Genetics.

Term: Cytology

Definition: The study of cell structure using optical techniques.

Which unit of measurement is typically used to describe the size of cells and organelles?

Micrometer (μm)

Which unit of measurement is used for molecules and structures too small for light microscopy?

Nanometer (nm)

Concept: Limit of Resolution

Definition: How far apart two objects must be to appear as distinct objects.

What term describes a microscope's ability to see fine details of a structure?

Resolving power

Friedrich Wohler demonstrated in 1828 that _____ could be synthesized from inorganic material.

Urea

What did Louis Pasteur demonstrate regarding yeast in the 1860s?

Living yeasts could ferment sugar into alcohol.

The discovery of enzymes was facilitated by the Buchners showing that _____ could perform fermentation.

Yeast extracts

Which scientist showed that ATP is the primary energy storage compound in cells?

Fritz Lipmann

Method: Centrifugation

Definition: A technique used to separate subcellular structures and macromolecules based on size, shape, or density.

Chromatography separates mixtures based on which molecular properties?

Size, charge, or affinity for specific molecules.

Which technique uses an electric field to separate macromolecules based on mobility through a gel?

Electrophoresis

What is the primary function of mass spectrometry in biochemistry?

Determining the size and composition of individual proteins.

Gregor Mendel is known for discovering the principles of segregation and _____.

Independent assortment

What was the original name given to DNA by Friedrich Miescher in 1869?

Nuclein

Who first described chromosomes and the process of mitosis in 1880?

Walther Flemming

The 'one gene-one enzyme' concept was formulated by which scientists?

Beadle and Tatum

How many covalent bonds can a single carbon atom form?

Four

Molecules composed only of carbon and hydrogen are called _____.

Hydrocarbons

Why are hydrocarbons important in the context of cellular barriers?

They are insoluble in water.

Which functional groups carry a negative charge at cellular pH?

Carboxyl and phosphate groups.

Amino groups are characterized by having a _____ charge.

Positive

Hydroxyl, sulfhydryl, carbonyl, and aldehyde groups are uncharged but _____.

Polar

What chemical property of water allows it to act as the universal solvent?

Polarity (unequal distribution of electrons).

The geometry of a water molecule is _____ rather than linear.

Bent

What type of bond forms between the electronegative oxygen of one water molecule and the electropositive hydrogen of another?

Hydrogen bond

Term: Hydrophilic

Definition: Describes solutes that have an affinity for water and dissolve easily.

The cellular membrane is a _____ permeability barrier.

Hydrophobic

What are the three main components of a cellular membrane?

Phospholipids, glycolipids, and membrane proteins.

Concept: Cellular Hierarchy

Definition: Biological molecules and structures organized into levels, each building on the preceding one.

Most cellular structures are made of linear polymers called _____.

Macromolecules

Principle: Self-assembly

Definition: Information required for spontaneous folding and interaction is inherent in the polymers themselves.

What is an example of a structure that depends on additional information from a preexisting structure for assembly?

Membranes (or cell walls).

In hierarchical assembly, what role do subassemblies play?

They act as intermediates between simple molecules and complex end products.

How does hierarchical assembly provide 'quality control' for a cell?

Defective components can be discarded at an early stage before being built into complex structures.

Which major class of biological molecules is technically not a polymer but shares similar synthesis methods?

Lipids

Proteins that function as catalysts to increase reaction rates are called _____.

Enzymes

What is the function of motility proteins?

Contraction and movement of cells and intracellular materials.

Regulatory proteins function by controlling and coordinating cell function based on _____.

The needs of the cell.

How many standard amino acids are used in protein synthesis?

20

Every amino acid contains a central α carbon, an amino group, a carboxyl group, and a unique _____.

R group (or side chain).

How many amino acids have nonpolar, hydrophobic R groups?

Nine

The immediate product of amino acid polymerization is a _____.

Polypeptide

The end of a polypeptide chain with a free amino group is the _____.

N-terminus (or amino terminus).

The end of a polypeptide chain with a free carboxyl group is the _____.

C-terminus (or carboxyl terminus).

When does a polypeptide officially become a functional protein?

When it has assumed a unique, stable 3D shape and is biologically active.

Term: Multimeric protein

Definition: A protein consisting of two or more polypeptide subunits.

What is the specific multimeric classification of hemoglobin?

Tetramer (two α and two β subunits).

Which type of covalent bond forms specifically between cysteine residues to stabilize protein folding?

Disulfide bond

Noncovalent interactions such as hydrogen bonds and van der Waals forces are individually weak but _____.

Collectively strong.

The unfolding of a polypeptide that usually results in loss of biological activity is called _____.

Denaturation

What is the specific spiral structure type of the main form of DNA in cells?

Right-handed spiral (B-DNA).

DNA strands are described as anti-parallel and _____ to each other.

Complementary

What is the chemical formula for D-glucose?

C6H12O6

Maltose is a disaccharide composed of two _____ units.

Glucose

Lactose is formed by the covalent linkage of glucose and _____.

Galactose

Which two monosaccharides combine to form sucrose?

Glucose and fructose.

The covalent bond that links monosaccharides together via an oxygen atom is a _____.

Glycosidic bond

What determines whether a glycosidic bond is classified as α or β?

The position of the hydroxyl (OH) group.

Which technique separated DNA strands to confirm DNA as the genetic material in the 1940s?

Experiments with bacteria and viruses.

Who proposed the double helix model for DNA structure in 1953?

Watson and Crick (with assistance from Franklin).

What is the primary role of structural proteins in the cell?

Providing physical support and shape to cells and organelles.

Which class of proteins enables a cell to respond to chemical stimuli from the environment?

Receptor proteins

In biochemistry, what is the role of metabolic intermediates?

They serve as precursors for the synthesis of small organic molecules like amino acids and nucleotides.

Why is high specific heat a biologically important property of water?

It allows water to absorb significant heat with minimal temperature change, stabilizing cell environments.