Biology Chapter 6 Study guide

Elements
basic chemical units that cannot be broken apart by chemical process.

How many naturally occuring elements are there?
90

How many elements are required by living things?
25

What elements is 96% of the human body composed of?
Oxygen, Hydrogen, Carbon, and Nitrogen

Trace element
critical elements found in the body in very small amounts.

What is an e xample of a trace element?
Iron

Each element consists of how many atoms?
one

atom
The smallest particle of an element that has the characteristics of that element.

Nucleus
center of the atom

Electron shells`
surround the nucleus at different energy levels

Proton
positive charge- in nucleus

Neutron
0 charge (nuetral) – in nucleus

Electron
Negative charge- orbits nucleus

What kinds of charges attract?
positive and negative

What is the greatest number of electrons in the first shell?
2

Isotope
Atoms of the same element that have different numbers of neutrons.

Unstable isotopes are what?
Radioactive

What can happen to the nucleus of an unstabble isotope?
It can decay spontaneously

What can happen to the particles and energy of an unstable isotope?
They can be given off.

Compound
2 o r more elements in a fixed ratio that are chemically combined.

Covalent bonds
Occur w hen 2 atoms share one or more pairs of electrons forming molecules.

Molecule
a group of atoms held together by covalent bonds having no overall charge.

ionic bonds
Attracting force between 2 ions of opposite charges

Ion
An atom that has gained or lost an electron

The resulting compound of an ion is what?
Electrically neutral.

Starting materials i n chemical reactions
Reactants

Resulting material
products

MAtter is not created or destroyed but ___.
Rearanged.

Fluid
mixture of 2 or more substances, consisting of a solvent and a solute.

Solute
Chemical that causes another substance to dissolve in a solution.

Solvent
The substance in a solution that is dissolved

Acid
Any substance that forms hydrogen ions in water

Base
Any substance that forms hydroxide ions in water.

OH combines with H+ to form what?
H2O

pH scale
Describes the acidity of solutions

pH
Potentital hydrogen

0 on pH scale
Most acidic

14 on pH scale
Most basic

pH of 7 is ___.
Neutral

Electronegative
An atom’s attraction for shared electrons

In water, ____ is electronegative
Oxygen

The oxygen in H2O forms what?
Polar covalent bonds

Polar covalent bonds
Shared electrons are pulled closer to the more electronegative atom.

The oxygen in H2O has a slightly what and 2 slightly what?
Negagative pole, positive poles

Hydrogen bonds in H2O are _____ chemical bonds.
Weak

Hydrogen bonds in H2O cause ______.
Cohesion

Cohesion
making water molecules stick together

Hydrogen bonds in H2O gives water a high_____.
surface tension

High surface tension
A measure of the d ifficulty to stretch or break the surface of a liquid.

Hydrogen bonds in H2O also cause _____.
Adhesion

Adhesion
An attraction between molecules of different substances

Water resists temperature changes and acts as an ____ that helps maintain a steady environment.
Insulator

Water ____ when it freezes.
Expands

Ice floats where?
On top

Water also helps to form _______.
New soil.

Diffusion
movement of molecules from an area of higher concentration to an area of lower concentration.

All moving objects have _____.
Kinetic energy

Kinetic energy
molecules are in motion

Brownium motion
The random motion of molecules

True/False: Diffusion requires energy.
False.

What 3 things is diffusion affected by?
Concentration, Temperature, and pressure.

Osmosis
Diffusion of water molecules

Temperature can do what to molecules?
Slow them down or speed them up.

Organic compounds
Compounds made by cells that contain carbon.

Carbon completes it’s outer shell by doing what?
Sharing electrons

Hydrocarbons
Compounds composed of only hydrogen and carbon

Carbon skeleton
Chain of carbon atoms in organic molecules

Carbon skeletons can vary in ____.
Length

True/false: Carbon skeletons can be branched and unbranched.
True

Carbon skeletons can have ______ bonds, varying in locations.
Double

Carbon skeletons may be arranged in _____.
Rings

Macromolecules
Giant molecules

Smaller units of macromolecules:
Monomers

Larger units of macromolecules
polymers

Chains of monomers
Polymers

Macromolecules are formed by ______.
Condensation.

Macromolecules are broken by:______.
Hydrolysis

Hydrolysis
A method by which polymers can be broken apart.

How is each element identified?
By a symbol

How many electrons can the second energy level hold?
8 electrons

How many electrons can the third energy level hold?
18 electrons

True/false: atoms contain different amounts of protons and electrons.
False

Metabolism
All of the chemical reactions that occur within an organism

Reactants
Substances that undergo chemical reactions.

Products
Substances formed by chemical reactions

Chemical equations must always be written so that they are _____.
Balanced

When elements combine to form compounds, do the elements take on new characteristics, or do they keep the original characteristics?
They no longer have their original properties.

Mixture
A combination of substances in which the individual components retain their own properties.

What percent range does water make up of organisms?
70 to 95 percent

When atoms in a covalent bond do not share electrons equally, they form what?
a polar molecule

polar molecule
a molecule with an uneual distribution of charge

Dynamic Equilibrium
Continuous movement but no overall concentration change

How many electrons does Carbon have in its outer energy level?
4

How is a double bond of Carbon formed?
Each atom shares 2 electrons.

isomers
Compounds with the same simple formula but different three dimensional structures.

Whats an example of 2 isomers?
Glucose and fructose

What are the 4 classes of Macromolecules?
Carbohyrdates, lipids, proteins, and Nucleic acids.

Carbohydrates range from______.
Small sugar molecules to large polysaccharides.

What are the monomers of Carbohydrates?
Monosaccharides

What is the function of Carbohydrates?
They are the main source of energy

What 3 elements make up Carbohydrates?
Carbon, hydrogen, oxygen.

What are the 2 polymers of Carbohydrates?
Polysaccharides and Disacharrides

What are 5 examples of Carbs?
Glucose, Starch, Cellulose, Glycogen, Sucrose

Dissacharide
A double sugar formed from 2 monosaccharides by dehydration synthesis.

Polysaccharides
Long chains of sugar units linked together by dehydration synthesis.

Polysaccharides can also be _____that cells break down to obtain sugar.
Storage molecules

Starch
Long term storage in plant roots and other tissues.

2 examples of starches?
Potatoes and grains

Glycogen
Long term energy storage in animals.

Where is glycogen stored in animals?
In the liver and muscle cells.

Cellulose
forms cable like fibrils in the tough walls that enclose plant cells.

Cellulose is a major component of what 2 things?
Wood and paper

Lipids
fats

What 2 elements do lipids mainly consist of?
Carbon and Hydrogen atoms linked by nonpolar covalent bonds

Hydrophobic
Water fearing

True/false: Lipids are hydrophobic.
True

What are the 2 main functions of lipids?
Energy storage and cell membranes

What is the most common type of lipid?
Glycerol + 3 fatty acids

Glycerol
A 3 carbon molecule that serves as a backbone for the lipid molecule.

Unsaturated
fats that have double bonds; do not solidify at room temperature

What kind of fats are unsaturated?
plant fats

Saturated
fats with the maximum number of hydrogen; solid at room temperature

What kindsof fats are saturated?
Animal fats

phospholipids
Major component of cell membranes

What are the 3 monomers of Lipids?
Fat, Phospholipid, Chlesterol/steroids

What are 4 examples of lipids?
Unsaturated fats, Saturated fats, Estrogen, Testosterone

Proteins
Essential to the structures and activities of life.

What is the monomer of Protein?
Amino acids (20 of them)

What elements make up proteins?
Carbon, hydrogen, oxygen, nitrogen, and usually sulfur.

What is the function of proteins?
Energy, Transport, structure

What are amino acids?
Have a central Carbon covalently bonded to 1 hydrogen, 1 amino group, 1 carboxyl group, and 1 chemical group.

How are amino acids linked together?
Dehydration synthesis.

Covalent linkage of amino acids form what?
A polypeptide bond

What is the polymer of proteins?
Polypeptide

What breaks apart polypeptides?
Hydrolysis

Enzymes
a protein that can change the rate of a reaction. (chemical catalyst)

Enzymes change the _____ of chemical reactions without chemically changing itself.
rate

What are 4 examples of proteins?
Enzymes, Hemoglobin-blood, Actin, Nyosin-muscle

Nucleic acid
a complex macromolecule that stores celluslar information in the form of a code.

What 5 elements make up nucleic acids?
Carbon, hydrogen, oxygen, nitrogen, phosphorus

What is the function of nucleic acids?
They store genetic information

What are the 2 types of nucleic acids?
DNA and RNA

DNA
genetic material inherited from parents

What are the monomers of nucleic acids?
Nucleotides (5 of them)

What are the 3 parts of a nucleotide?
5 Carbon sugar, phosphate group, nitrogenous base

What are the 5 different nucleotides?
Adenine, Guanine, Thymine, Cytosin, and Uracil (only in RNA)

DNA is what shape?
A double helix

What is t he polymer of Nucleic acid?
Nucleic acids

What are 2 examples of nucleic acids?
DNA and RNA

Tagged In :

Get help with your homework


image
Haven't found the Essay You Want? Get your custom essay sample For Only $13.90/page

Sarah from studyhippoHi there, would you like to get such a paper? How about receiving a customized one?

Check it out