Biological Molecules Practice Flashcards

Vocabulary-style flashcards covering biological molecules, food tests, and DNA structure based on lecture notes.

Carbohydrates

Organic compounds manufactured by green plants during photosynthesis, made of carbon ($C$), hydrogen ($H$), and oxygen ($O$).

Glucose

The smallest basic unit of carbohydrates.

Starch test result (Positive)

When iodine solution is added to food, the solution turns blue-black if starch is present.

Starch test result (Negative)

The iodine solution remains yellow or light brown if starch is absent.

Reducing sugars

Sugars including glucose, maltose, galactose, fructose, and lactose that reduce Benedict's solution to form a precipitate.

Sucrose

The only sugar mentioned in the text that is not a reducing sugar.

Benedict's test result (High concentration)

The solution changes slowly from deep blue to orange to brick red.

Benedict's test result (Low concentration)

The solution changes slowly from deep blue to green to yellow.

Proteins

Molecules containing carbon ($C$), hydrogen ($H$), oxygen ($O$), and nitrogen ($N$); some also contain sulfur ($S$) and phosphorus ($P$).

Amino acid

The smallest basic unit of protein.

Haemoglobin

A protein found in red blood cells that contains iron ($Fe$).

Casein

A protein found in milk that contains iron ($Fe$).

Biuret test result (Positive)

The solution turns from blue to purple (or violet or mauve) indicating the presence of protein.

Lipids

A collective term for fats (solid at room temperature) and oils (liquid at room temperature).

Fat molecule composition

Built up from three fatty acids molecules chemically joined to one glycerol molecule.

Condensation reaction (Fats)

A reaction where three fatty acids link to one glycerol molecule with the elimination of water to form fat.

Ethanol emulsion test result (Positive)

A milky/white emulsion shows the presence of fats when food dissolved in ethanol is poured into water.

DCPIP

A dark blue liquid used to test for Vitamin C; it becomes colourless if Vitamin C is present.

Nucleotide

The chemical compound making up DNA, consisting of a sugar molecule, a phosphate molecule, and a base.

DNA Bases

The four types of bases in DNA: Adenine, Guanine, Cytosine, and Thymine.

Base-pairing

The formation of hydrogen bonds where Adenine pairs with Thymine, and Guanine pairs with Cytosine.

Double helix

The three-dimensional, spiral-like shape formed by two strands of DNA joined by hydrogen bonds.