Unit 1 Review: The Chemistry of Life (Video)

Flashcards covering key concepts from Unit 1 Biology notes on the chemistry of life, water, macromolecules, protein/nucleic acid structure, and basic experimental concepts.

What are functional groups?

Specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules; they determine overall polarity and reactivity.

What is the independent variable in an experiment?

The variable being tested or deliberately changed to test its effect.

What is the dependent variable?

The variable being measured to determine the effect of the independent variable.

What is the role of positive/negative controls and constants in an experiment?

Controls establish baselines; constants are factors kept the same across all conditions.

What is the null hypothesis versus the alternative hypothesis?

Null: there is no effect. Alternative: there is an effect; the expected results align with the hypothesis.

What does Standard Error of the Mean (SEM) measure?

The variability of the sampling distribution; how far the sample mean is likely to be from the population mean.

How are error bars with \pm2 SEM typically interpreted on graphs?

They represent the range around the mean that approximates 95% confidence for the estimate.

If error bars do overlap, what does that suggest about the means?

The means are not significantly different.

Why do polarity and hydrogen bonding matter for water’s biological function?

They drive water’s cohesion, adhesion, solvent properties, heat capacity, and temperature regulation.

What is a polar covalent molecule?

A molecule with an uneven distribution of charge due to differences in electronegativity (e.g., H2O).

What is hydrogen bonding?

A strong intermolecular attraction between a hydrogen atom bonded to N, O, or F and a lone pair on another N, O, or F.

How many hydrogen bonds can a single water molecule form with neighbors?

Up to four hydrogen bonds with four neighboring water molecules.

Define cohesion.

Attraction between water molecules via hydrogen bonding.

Define adhesion.

Attraction of water molecules to other polar molecules via hydrogen bonding.

What does high specific heat mean for water?

It takes more energy to raise water’s temperature due to hydrogen bonding.

What is evaporative cooling?

Surface cooling as the most energetic molecules leave the liquid by evaporation.

Why does ice float on water?

Solid ice is less dense than liquid water due to its crystalline structure.

What does the term 'versatile solvent' mean for water?

Water dissolves ionic and polar covalent solutes.

What elements compose carbohydrates?

Carbon, Hydrogen, and Oxygen (C, H, O).

What elements compose lipids?

Carbon, Hydrogen, and Oxygen (C, H, O); phosphorus in phospholipids.

What elements compose proteins?

Carbon, Hydrogen, Oxygen, Nitrogen; sulfur in some R groups.

What elements compose nucleic acids?

Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus (C, H, O, N, P).

What is the difference between polymers and monomers?

Polymers are large molecules made of repeating monomer units; monomers are the building blocks.

What are monosaccharides and polysaccharides in carbohydrates?

Monosaccharides are simple sugar units; polysaccharides are polymers of monosaccharides.

What are glycosidic bonds?

Bonds that join monosaccharides in carbohydrates.

What are the main lipid classes?

Triglycerides (glycerol + three fatty acids), phospholipids (two fatty acids + glycerol + phosphate), steroids (four fused carbon rings).

Describe triglyceride structure.

Glycerol linked to three fatty acids via ester bonds.

What distinguishes saturated vs. unsaturated fatty acids?

Saturated: all C–C single bonds; solid at room temperature. Unsaturated: one or more C=C bonds; liquid at room temperature.

What does amphipathic mean for phospholipids?

Phospholipids have a polar, hydrophilic head and nonpolar, hydrophobic tails.

What are the primary functions of proteins?

Structure, signaling, catalysis, and other roles in cells.

What are the termini of a protein, and what do they signify?

Amino terminus (N-terminus, -NH2) and carboxyl terminus (C-terminus, -COOH).

How are protein R groups categorized?

By hydrophobic, hydrophilic, or charged/ionic properties.

What are the four levels of protein structure?

1°: sequence; 2°: alpha helices and beta sheets; 3°: overall 3D shape; 4°: interactions between multiple polypeptides.

Can 2°, 3°, and 4° structures be denatured? Why or why not?

Yes; changes in temperature or pH disrupt non-covalent interactions, altering structure and function.

What defines the ends of nucleic acids?

The 5′ end (phosphate) and the 3′ end (hydroxyl) on the sugar.

What are the structural differences between DNA and RNA?

DNA uses deoxyribose and thymine; RNA uses ribose and uracil; DNA is usually double-stranded and antiparallel; RNA is usually single-stranded.

What are the components of a nucleotide?

A sugar (deoxyribose or ribose), a phosphate group, and a nitrogenous base; connected with covalent bonds forming a 5′ to 3′ backbone.

What are the base-pairing rules?

A pairs with T (2 hydrogen bonds); C pairs with G (3 hydrogen bonds).

What is the orientation of the DNA double helix?

Antiparallel: the two strands run in opposite 5′ to 3′ directions.

During nucleic acid synthesis, to which end are nucleotides added?

The 3′ end of the growing strand.

What functional group has oxygen bonded to hydrogen (–OH)?

Hydroxyl Group

What functional group has carbon double-bonded to oxygen ( \text{C=O} )?

Carbonyl Group

What functional group has a carbonyl group bonded to a hydroxyl group ( \text{-COOH} )?

Carboxyl Group

What functional group has nitrogen bonded to two hydrogens ( \text{-NH}_2 )?

Amino Group

What functional group has sulfur bonded to hydrogen ( \text{-SH} )?

Sulfhydryl Group

What functional group has phosphorus bonded to four oxygens, with at least one oxygen double-bonded to the phosphorus ( \text{-PO}_4 )?

Phosphate Group