Lab 2 Biological Molecules Flashcards Preview

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Flashcards in Lab 2 Biological Molecules Deck (19):
1

Macromolecules

Large molecules that are made of smaller sub-unit molecules

2

Four most common organic molecules found in all living organisms

Carbohydrates, proteins, lipids and nucleic acid

3

Polymers

Some macromolecules are polymers. Polymers are made up of repeating units called monomers.
For example, proteins are made up of chains of amino acids, starch is a chain of glucose molecules, and nucleic acids are chains of nucleotides.
Lipids are not polymers. Its structure is not a repeating chain of monomers.

4

Control

The experimental group must always be accompanied by a control.
Ensures the effect observed in the experiment are the result of the phenomenon being test and not from another unidentified source.
Also give a baseline to which they compare their experimental results.

5

Negative control

Something that will get a negative result in testing.

6

Positive control

When you are using a solution you know contains the macromolecule you are testing for.
Should get a positive result.

7

Replication

Test should always be performed more than once to ensure that the initial results are repeatable.
It gives the experimenter confidence in their results.

8

Carbohydrates

Compounds composed of carbon, hydrogen, and oxygen with a ratio of 1:2:1.
This group includes sugars, starch, cellulose, and glycogen.

9

Monosaccharides

The simplest carbohydrates are monosaccharides. The most common are glucose (which often serves as an energy source in cells)

10

Benedict's reagent

Is used to test for glucose in a solution.
Any colour change from blue is considered a positive test result.

11

Polysaccharides

Are large molecules of numerous monosaccharide components.
This is often an efficient way for cells to store energy.
Liver cells and muscle cells store glucose in the form of glycogen.
Some plant cells store glucose in the form of starch.

12

Iodine

Tests for starch.
It changes from yellow brown to a very dark blue black.

13

Protein

Proteins are polymers of amino acids.
A protein is made up of one or more polypeptide chains.

14

Biuret reagent

To test for proteins.
Changes from light blue to purple in presence kf protein.

15

Enzymes

Molecules that catalyze chemical reactions

16

Hormones

Chemical.messengers in the body

17

Denatured

A proteins exposure to extremes of temperature or oh causes the weaker hydrogen binds that are responsible for a second and tertiary structure to break. Result is unfolding and loss of biological function.

18

Lipids

One of the distinguishing features of these molecules is that they are insoluble in water.
Fatty acids vary in chain length and can be saturated (contain no double bonds) or unsaturated (contain one or more double bonds)
Fats serve as a long term energy source.
Adipose tissue is a form of connective tissue that is specialized in storing fats. Found beneath the skin surrounding various organs.

19

Sudan IV test

Based on two characteristics of lipids.
They are not polar and therefore insoluble in water.
They are less dense than water.
The reagent is also non polar and therefore does not dissolve in water or other polar substances, but will dissolve in lipids and turn bright red in colour.
Positive test would be
The top layer becomes bright red (a positive test)
The water stays at the bottom, and it may have some dark, undissolved Sudan IV particles in it.