Biochemistry Unit 1: Water, Macromolecules, and Enzymes

Complete set of flashcards covering biochemistry basics including water properties, macromolecules (carbs, lipids, proteins, nucleic acids), cell membrane transport, and enzyme kinetics based on class lecture notes.

What are the four primary signs of life according to the transcript?

Reproduction, growth, metabolism, and response to stimuli.

Explain the difference between catabolism and anabolism.

Catabolism is the process of breaking down large molecules into subunits, while anabolism is the process of taking small subunits to create larger molecules.

Why is water considered a bent molecule rather than a linear one?

Water is bent because oxygen has a higher electronegativity than hydrogen, causing unequal electron sharing, and it has two pairs of non-bonding electrons that repel each other.

What is the definition of electronegativity?

The ability of an atom to attract bonding electrons to itself.

What type of bond is formed if the electronegativity difference between two atoms is less than $0.4$?

A covalent bond, where electrons are shared.

What type of bond is formed if the electronegativity difference is greater than $1.7$?

An ionic bond, where electrons are transferred.

At what temperature does liquid water become less dense?

At around $4^\text{ o}C$.

List the four types of intermolecular forces from strongest to weakest.

1. Ion-dipole, 2. Hydrogen bond, 3. Dipole-Dipole, 4. London dispersion.

What provides a solution with acidic properties like sour taste and the ability to turn blue litmus red?

The presence of the hydronium ion ($H_3O^+$).

What is the normal pH of human blood, and what range of change is considered fatal?

The normal pH is $7.4$. An increase or decrease of $0.2 - 0.4$ is fatal.

How does the bicarbonate-carbonic acid buffer system handle basic substances in the bloodstream?

Carbonic acid ionizes to release $H$ ions back into the bloodstream to neutralize the base.

What defines an organic compound?

Any molecule that has a carbon-hydrogen backbone.

What are the four primary functional groups mentioned in the notes and their general roles?

1. Hydroxyl group ($OH$): adds polarity. 2. Carboxyl group ($COOH$): makes molecules acidic. 3. Amino group ($NH_3$): makes molecules basic. 4. Phosphate group: holds nucleotides.

What is the general chemical formula for carbohydrates?

$(CH_2O)_n$ where $n$ represents the number of carbon atoms.

Why are glucose, fructose, and sucrose not considered polymers?

Because they are classified as monosaccharides or disaccharides, while polymers (like starch or cellulose) are made of many repeating subunits.

What is the difference between a condensation/dehydration reaction and a hydrolysis reaction?

Condensation removes water to join subunits (anabolic), while hydrolysis adds water to break bonds between subunits (catabolic).

What is the difference between alpha and beta glucose rings?

In an alpha sugar, the hydroxyl ($OH$) group is below carbon 1; in a beta sugar, the hydroxyl group is above carbon 1.

Starch is composed of which two polysaccharides?

Amylose (non-branched/linear) and Amylopectin (branched).

Why can humans not digest cellulose?

Humans do not possess enzymes to hydrolyze the beta 1-4 linkages found in cellulose.

What is chitin and where is it found?

Chitin is a cellulose-like polymer of N-acetylglucosamine found in the exoskeletons of insects and crustaceans and the cell walls of fungi.

What are the components of a fat molecule?

One glycerol (a three-carbon alcohol) and three fatty acid tails (long hydrocarbon chains).

How do Cis and Trans fats differ in their geometric orientation?

In Cis orientation, $H$ atoms are on the same side of the $C=C$ double bond; in Trans orientation, they are on opposite sides.

What is the structure of a phospholipid?

A glycerol molecule attached to two nonpolar fatty acid tails and one polar phosphate functional group.

How many essential and non-essential amino acids are there for humans?

There are 8 essential amino acids (must be consumed) and 12 non-essential amino acids (produced by the body).

What are the four levels of protein structure?

Primary (unique amino acid sequence), Secondary (alpha helix or beta-pleated sheet), Tertiary (3D folding), and Quaternary (multiple polypeptides joined).

What is denaturation in proteins?

The disruption of a protein's 3D shape due to changes in pH, temperature, or chemicals, which causes the protein to stop functioning.

What are the base pairing rules for DNA nitrogenous bases?

Adenine bonds with Thymine (two hydrogen bonds) and Guanine bonds with Cytosine (three hydrogen bonds).

What determines the fluidity of a cell membrane?

The saturation of lipid tails (unsaturated tails create more fluidity due to kinks) and temperature (sterols act as stabilizers).

What is the difference between primary and secondary active transport?

Primary active transport moves ions directly against gradients (e.g., $Na^+$, $K^+$), while secondary active transport uses the energy from those gradients to pump other molecules.

What is 'induced fit' in enzyme activity?

The slight change in the shape of an enzyme's active site to better accommodate a substrate once it has bound.

What happens during competitive inhibition of an enzyme?

A competitor molecule that closely resembles the substrate binds to the active site, blocking the actual substrate from binding.