biology review 3

What element forms the framework of biological molecules?

Carbon

What are the four main types of biological macromolecules?

Carbohydrates, Lipids, Proteins, Nucleic Acids

How many covalent bonds can a carbon atom form?

Up to four covalent bonds

What is the empirical formula for carbohydrates?

(CH2O)n

What is the primary function of carbohydrates?

Energy storage and structural support

What are the building blocks of proteins?

Amino acids

What are lipids primarily used for in biological systems?

Energy storage and membrane structure

What is the role of nucleic acids in cells?

Information storage and transfer

What is polymerization?

The process of linking monomers to form polymers

Define dehydration synthesis.

The formation of large molecules by the removal of water

What is hydrolysis?

The breakdown of large molecules by the addition of water

What are functional groups?

Specific molecular groups that bond to carbon-hydrogen cores and influence the behavior of molecules

What are isomers?

Molecules with the same molecular or empirical formula but different structures

What are structural isomers?

Isomers that differ in the structure of their carbon skeleton

What are stereoisomers?

Isomers that differ in how groups are attached

What are enantiomers?

Chiral molecules that are mirror images of each other

What is the significance of the thalidomide tragedy?

It highlighted the importance of stereochemistry in drug safety

What is the role of enzymes in chemical reactions?

They catalyze reactions and can function outside of living cells

What type of bond holds carbon atoms together in hydrocarbons?

Covalent bonds

What is the primary function of proteins in biological systems?

Catalysis, transport, structural support, and signaling

What are triglycerides?

Lipids used for energy storage, composed of glycerol and three fatty acids

What is the function of cellulose?

Structural support in plant cell walls

What are glycoproteins and glycolipids involved in?

Cell recognition and signaling

What are the two types of nucleic acids?

DNA and RNA

What is the role of ribozymes?

Catalysis in biological reactions

What is the significance of phospholipids?

They are essential for membrane structure

What is the role of cholesterol in biological systems?

Membrane structure and hormone production

What are terpenes?

Long carbon chains that serve as pigments and structural support

What are monosaccharides?

The simplest carbohydrates.

What is the chemical formula for glucose?

C6H12O6

What is fructose in relation to glucose?

Fructose is a structural isomer of glucose.

What is galactose in relation to glucose?

Galactose is a stereoisomer of glucose.

What are disaccharides?

Two monosaccharides linked together by dehydration synthesis.

Give an example of a disaccharide.

Sucrose, lactose, or maltose.

What type of bond links monosaccharides in disaccharides?

Glycosidic bond.

What is the role of disaccharides in plants?

They serve as transport forms of glucose.

What are polysaccharides?

Long chains of monosaccharides linked through dehydration synthesis.

What polysaccharide do plants use for energy storage?

Starch.

What polysaccharide do animals use for energy storage?

Glycogen.

What is cellulose?

A structural polysaccharide in plants made of long, unbranched β-linked chains.

What is chitin?

A polymer of N-acetylglucosamine, a nitrogen-containing derivative of glucose.

Why can cows digest cellulose but humans cannot?

Cows have cellulose-digesting bacteria that produce cellulase.

What are nucleic acids composed of?

Polymers made of monomers called nucleotides.

What are the components of a nucleotide?

Sugar, phosphate, and nitrogenous base.

What sugar is found in DNA?

Deoxyribose.

What sugar is found in RNA?

Ribose.

What are the purines in nucleic acids?

Adenine and guanine.

What are the pyrimidines in nucleic acids?

Thymine, cytosine, and uracil.

What is the structure of DNA?

A double helix made of two polynucleotide strands.

What are the base-pairing rules in DNA?

Adenine pairs with Thymine, and Cytosine pairs with Guanine.

What is the primary energy currency of the cell?

Adenosine triphosphate (ATP).

What are the functions of proteins?

Enzyme catalysis, defense, transport, support, motion, regulation, and storage.

What are proteins composed of?

Polymers made of long, unbranched chains of amino acids.

What is a peptide bond?

A bond formed between the amino end and carboxyl end of two adjacent amino acids.

What determines a protein's function?

The shape of the protein.

What is a zwitterion?

A molecule containing an equal number of positive and negative charges, resulting in a net zero charge.

What is the primary structure of a protein?

The sequence of amino acids (polypeptides) in a protein.

How many different sequences can a protein with 100 amino acids form?

A protein with 100 amino acids can form any of 20^100 different sequences.

What characterizes the secondary structure of proteins?

The interaction of groups in the peptide backbone, forming structures like helices and sheets.

What is an example of a protein that has a helical secondary structure?

DNA binding domain.

What is an example of a protein that has a sheet secondary structure?

Porin protein that forms holes in membranes.

What is the tertiary structure of a protein?

The final folded shape of a globular protein, stabilized by various forces.

What is the quaternary structure of a protein?

The arrangement of individual chains (subunits) in a protein with two or more polypeptide chains.

What are motifs in protein structure?

Short, recurring patterns of secondary structure that provide clues about a protein's overall fold or function.

What are domains in protein structure?

Larger, independently folding structural and functional units within a protein.

How do motifs and domains relate to protein structure?

Secondary structures (helix, sheet) → Motifs (super secondary) → Domains → Whole protein.

What role do chaperone proteins play in protein folding?

Chaperones assist proteins in folding correctly and prevent misfolding.

What is denaturation in proteins?

The loss of a protein's structure due to environmental conditions, leading to loss of function.

What environmental factors can cause protein denaturation?

pH, temperature, and ionic concentration of the solution.

What hypothesis did Christian Anfinsen propose regarding protein folding?

The 3-D structure of a protein is determined by its amino acid sequence and environmental conditions.

What is the N-terminal rule in protein degradation?

The N-terminal amino acid of a protein determines its half-life.

Which amino acids lead to a short half-life in proteins?

Leucine, phenylalanine, tryptophan, or tyrosine.

What is the role of Clp S in protein degradation?

Clp S recognizes destabilizing signals and presents proteins to the bacterial Clp AP protease for degradation.

What are the characteristics of lipids?

Lipids are a loosely defined group of molecules that are insoluble in water.

What is the significance of the tertiary structure in proteins?

It is the final level of structure for proteins consisting of only a single polypeptide chain.

What stabilizes the tertiary structure of proteins?

A number of forces, including hydrogen bonds and interactions among side chains.

What are heat-shock proteins (HSPs)?

Proteins that increase in response to high temperature stress and help prevent protein denaturation.

What is the relationship between protein misfolding and diseases?

Protein misfolding is thought to be the primary cause of many degenerative and neurodegenerative disorders.

What is the role of molecular chaperones?

They assist in the conformational folding or unfolding of large proteins or macromolecular protein complexes.

What happens to a denatured protein when allowed to renature under native conditions?

It will refold into its native structure if the conditions are suitable.

What is the significance of the thermodynamic hypothesis in protein folding?

It states that the 3-D form of a protein is determined by its amino acid sequence and folding environment.

What is the result of improper protein folding?

It can lead to diseases such as cystic fibrosis and neurodegenerative disorders.

What is the function of the GroE chaperonin?

It helps proteins fold correctly, preventing misfolding.

What characteristic of C-H bonds makes lipids hydrophobic?

The high proportion of nonpolar C-H bonds.

What are the main types of lipids mentioned?

Fats, oils, waxes, terpenes, steroids, and some vitamins.

What are triglycerides composed of?

One glycerol and three fatty acids.

What is the difference between saturated and unsaturated fatty acids?

Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

What is the melting point difference between saturated and unsaturated fats?

Saturated fats have a higher melting point and are typically of animal origin, while unsaturated fats have a lower melting point and are usually of plant origin.

What are trans fats?

Trans fats are unsaturated fats that have been industrially modified to become solid at room temperature.

What are phospholipids composed of?

Glycerol, two fatty acids (nonpolar tails), and a phosphate group (polar head).

What is the function of phospholipids in biological membranes?

They form all biological membranes.

What is a micelle?

A structure where lipid molecules orient with polar heads toward water and nonpolar tails away from water.

What is a phospholipid bilayer?

A structure where two layers of phospholipids form, with hydrophilic heads pointing outward and hydrophobic tails pointing inward.

What is the role of functional groups in organic molecules?

Functional groups determine the characteristics and reactivity of organic molecules.

What is the monomer of carbohydrates?

Monosaccharides.

What is the polymer formed from monosaccharides?

Starch.

What is the monomer of nucleic acids?

Nucleotides.

What polymer is formed from nucleotides?

DNA strands.

What is the monomer of proteins?

Amino acids.

What is the polymer formed from amino acids?

Polypeptides.