Exam 1 Review

Question 1

What is an element? What components make up an element?

Answer 1

A material that cannot be broken down to any simpler form, component that makes up an element is the atom

Question 2

Describe an atom. Be able to label it and know where the charges go

Answer 2

Atom is a proton, electron and neutron. Smallest unit of matter that still display the element

Question 3

What are the three types of chemical bonds? What are their characteristics?

Answer 3

Ionic bond: an electrostatic attraction between two opposite charged ions, Hydrogen bond: hydrogen atom with an electronegative atom, Covalent bond: atoms that are bound by sharing electrons to attain stable configurations.

Question 4

What are functional groups? Why do we care about them in food science?
What is their purpose? Do not worry about memorizing the different types

Answer 4

Functional groups are alcohol (OH), amino (NH2), and carboxylic (COOH), and Ester group (compounds of alcohol, fats, and oil). Alters how food changes color, spoil ripens.

Question 5

What is an enzyme? How does it work? Be able to label an enzymatic reaction

Answer 5

Enzym is a substance that is produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.

Question 6

What enzymes do our body to breakdown food? Where are they found in the body? (For Lipase, use info on slide)

Answer 6

Pepsin (protein) GI tract, Lipase (fats) liver, Amylase (starch) saliva

Question 7

What is oxidation? Reduction? Enzymatic- oxidation? Hydrolysis? Understand what they do. Basic info

Answer 7

Oxidation is the addition of oxygen and remove a hydrogen
Reduction is gaining of hydrogen and loss of oxygen
Enzymatic is browning (like a banana)

Question 8

Describe the structure of water. Where are the charges? Why does it have a tetrahedral structure?

Answer 8

H2O: Dipolar, 105 degree angle-Tetraheadryal, covalent bond between hydrogen and oxygen. Positive charge on the hydrogens

Question 9

Why is considered dipolar? How does its charge relate to it being the universal solvent?

Answer 9

Dipolar because of the 2 hydrogen atoms, universal solvent because it is a neutral pH, and can easily be created r broken with hydrogen.

Question 10

Know the bonds within a single molecule and between molecules.

Answer 10

Covalent
Ionic
Hydrogen

Question 11

Know how to convert temperature and adjust the boiling pt base on atmospheric pressure

Answer 11

Fahrenheit -> Celsius: subtract 32, multiple 5, divide 9.
Celsius -> Fahrenheit: mult 9, divide 5, add 32
Adjusting Boiling Point
Subtract Standard Pressure (1atm or 760mmHg) from current, divide by 28 mmHg add to 100*C

Question 12

What is water activity (basic definition not the equation)? What does it measure? Why is this measurement important? How is it used in food science? What are the important values?

Answer 12

Water activity is based on absorbed water: loosely held by hydrogen bond, hard to release b.c bond, bound water: difficult to remove, held tight by chemical reaction; and free water: often lost or gained during storage, vapor pressure of water.

Question 13

What types of water are in our foods? Describe them

Answer 13

Free Water
Absorbed Water
Retained Water

Question 14

What does it mean if something is a solvent? What does it mean if something dissolves in water? What does water do with amphiphilic molecules?

Answer 14

Solvent: liquid substance that is capable of dissolving other substances.. When an atom/molecule is torn from one another are are displaced throughout the solvent. Amphiphilic molecules tends to have polar, water soluble group attached to a non soluble, water insoluble hydrocarbon chain.

Question 15

What are the Physicochemical States? Understand the Amorphous states and how foods can change states. Be sure to relate this to the glass transition temp

Answer 15

Physiochemical states: how water and food chemicals move together→ Crystallin: solid, low mobility of molecules (ice); Liquid- Freedom movement, has the highest degree of movement -> ketchup, flowable, water; Amorphous: rubbery, soft, pliable, glassy- hard.
All depends on temperature

Question 16

How do molecules move in our food?

Answer 16

Newtonian viscosity is constant (water), non newtonian (ketchup)

Question 17

What are carbohydrates? Why do we need to consume them? How many calories do they provide? What is the simplest form? What is a disaccharide (know the monosaccharaides that make these)? Polysaccharide? Know characteristics for each type of carbohydrate (excluding pectic substances and gums). What bond holds carbohydrates together?

Answer 17

Carbohydrates: main fuel source, breaks down to glucose=energy source. Provides 4 g/cal, contains carbon, hydrogen and oxygen. Disaccharide: sucrose, lactose, maltose, -> puttiong two mono’s together. Monosaccharides: Simple sugar- glucose, fructose, galactose, mannose; different between the arrangement of elements. Polysaccharides are a carbohydrate that consist of (cellolose , starch or glycogen) whose molecules consist of a number of sugar molecules bonded together.

Question 18

Why do we care that sugar is a humectant? Think about food preservation

Answer 18

It impacts water activity, and affects water. forms hydrogen bonds w/ water. Type of syrup

Question 19

What is the glycemic index? How does this relate to the glycemic effect?

Answer 19

Glycemic Index: how much sugar can be taken on blood sugar level. Glycemic effect can happen when someone has too much sugar and levels rise too fast.

Question 20

What is a sugar alcohol? Know the example given and its characteristics

Answer 20

A sugar alcohol from a carbohydrate whose carbonyl group has been reduced to a hydroxyl group