General Biology 1111 Terms

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge and found outside the nucleus

Mass of a proton

1 amu (atomic mass unit)

Mass of a neutron

1 amu (atomic mass unit)

Mass of an electron

The mass of an electron is negligible.

What determines the atomic number of an element?

The number of protons in the nucleus

Valence electrons

Electrons in the outermost shell of an atom.

Chemical bond

The attraction between atoms usually involving negatively charged electrons.

Octet rule

Atoms desire to have 8 electrons in their outermost shell to achieve stability

Ionic bonds

A chemical bond in which electrons are transferred from one atom to another. (One loses electrons while the other gains them)

Covalent bonds

A chemical bond that involves the sharing of electron pairs between atoms

Ion

A charged atom

Molecule

Two or more atoms connected through covalent bonds.

Non-polar covalent bond

Electrons are shared equally between atoms in the bond.

Independent Variable

What you are manipulating in hopes of affecting the dependent variable, the potential cause

Dependent Variable

What you are measuring/care about, the outcome or effect

Hypothesis

Proposed explanation for observed phenomena, answer to scientific question

Characteristics of Living Things

1) Organization

2) Metabolism

3) Regulation

4) Response to Environment,

5) Growth, Development, and Evolution

6) Reproduction

Science

Way of looking at the world based on evidence, large samples and average outcomes draw conclusions

Anecdote

Individual stories are used as evidence, can suggest things that should investigated, not a trustworthy source

Negative Control

Independent variable will not affect dependent variable

Positive Control

Independent Variable will affect the dependent variable in a measurable way

Experimental/Treatment

Unknown outcome, what you are testing

Standardized Variable

Things that are kept the same for treatment and control groups to isolate causes and effects

Scientific Method

Reading others’ work

Electronegativity

Concentration of positive charge in the nucleus

Vaan der Waals Interaction

Electron distribution changes within atoms, asymmetrical electron distribution causes temporary patches of positive and negative charges, atoms “stick” to each other

Hydrogen Bonding

Attraction between partially charged atoms created by polar covalent bonds, they are transient (constantly broken / reformed)

Cohesion

The tendency of water molecules to stick together due to hydrogen bonding, results in surface tension.

Adhesion

Water molecules can cling to surfaces of other materials rather than just to each other, can result in capillary action. Happens due to hydrogen bonding in water molecules.

Capillary Action

The movement of water through a narrow tube without the assistance of external forces. Caused by adhesion, surface tension, and cohesion.

Heat

The total movement of a body of matter

Temperature

the average speed of molecules, measure of heat intensity

Surface Tension

the ability to break the surface of water

Specific Heat

energy (heat) it takes to raise the temperature of 1 gram by 1°C

Heat of Vaporization

energy (heat) to convert 1 gram of liquid to gas

Evaporative Cooling

Fastest (hottest) molecules evaporate, average speed (temperature) drops

Hydrophilic

Polar molecules, contain oxygen or nitrogen bound to hydrogen, ions and charged molecules, dissolve in water

Hydrophobic

Non-polar molecules, made of almost only carbon and hydrogen, separate in water

Acids

Increase [H+], [H+] donor, and pH is less than 7

Bases

Decreases [H+], [H+] acceptor, pH is more than 7

Functional Groups

chemical groups that influence molecular function by participating in chemical reactions, tend to include elements other than carbon and hydrogen

Biological Molecules

Lipids, Nucleotides, Proteins, and Carbohydrates

What are biological molecules built on?

Chains of carbon bonded to hydrogen

Polymers

Large molecules made of repeated units of repeated units of simple molecules called monomers. Process is known as Polymerization.

Monomers vs. Oligomers vs. Polymers

Monomer: 1

Oligomers: n= 2 to 99

Polymers = n ≥ 100

Hydrolysis

Disassembly

Water breaks chemical bonds into smaller molecules/components.

Polymer ——> Monomer

Water is added causing bonds to break.

Dehydration/Condensation

Synthesis

Chemical Reaction where two molecules combine to form a larger molecule, releasing water in the process.

Monomer ——> Polymer

Function of Carbohydrates

Energy storage, cell structure

Function of Lipids

Membrane Structure, energy storage

Function of Proteins

Cell structure, and molecular machines

Function of Nucleic Acids

Information storage and processing

What is the most important carbohydrate to living things?

Glucose

Where is glucose stored in plants?

Starch

Where is glucose stored in animals?

Glycogen

What are lipids made of?

Carbons and Hydrogens

Non-polar covalent bonds

What is the structure of triglycerides?

3 Fatty Acids + Glycerol

What is the structure of unsaturated fats?

Carbon-Carbon double bonds which make the strands bent

What do saturated fats look like at room temperature?

Solid

Unsaturated fats at room temperature

Liquid

Structure of a phospholipid.

A hydrophilic Phosphate head and a hydrophobic fatty acid tail

Polar Section of phospholipid

The head

Nonpolar section of phospholipid

The tail

Phospholipid bilayer

Phospholipids form two sheets with the tails facing each other

Function of phospholipid bilayer

Helps cells regulate their internal environment through diffusion across a membrane

Genetic Material

Substance that contains the information for how to build an organism, and for what each cell should do

What did the experiment conducted by Oswald Avery, Colin MacLeod, and Maclyn McCarty prove? How did they do it?

It proved that DNA is genetic material.

DNA Genome

Holds the information for how to build every protein in the cell

Structure of DNA

Two strands of Nucleotides linked by covalent bonds and held together by hydrogen bonds

What are the four nitrogenous bases in DNA?

Adenine, Thymine, Guanine, and Cytosine

Structure of Nucleotides

A phosphate group, a sugar molecule, and nitrogenous base

Name the pyrimidines.

Thymine and Cytosine

Name the purines.

Adenine and Guanine

In a nucleotide, where is the phosphate group attached?

The 5’ carbon atom of the sugar

In a nucleotide, what is located on the 3’ carbon atom of the sugar?

A hydroxyl group

What did Erwin Chargaff discover?

Amount of Adenine = Amount of Thymine

Amount of Guanine = Amount of Cytosine

What are the key features of DNA?

Anti - parallel strands, one strand: 5’ to 3’ and the other: 3’ to 5’

Sugar phosphate “backbones”

Bases held together by Hydrogen bonds

How many bonds are there between Adenine and Thymine?

Two

How many bonds are there between Guanine and Cytosine?

Three

What is different about RNA compared to DNA?

RNA is single stranded, has Cytosine instead Thymine, and its sugar is ribose.

Nucleotide Uracil bonds to in RNA

Adenine

Origin of replication

Specific sites (sequences) where DNA replication starts

Replication Bubble

Expanding area of replicated DNA

DNA Polymerase

Adds new strands of nucleotides to the 3’ end of an adjoining strand to make a continuous DNA strand from the fragments

Cells you would not want to be shortened by Telomerase

Gamete-Producing cells and Stem Cells

DNA Helicase

Separates DNA strands from each other

Topoisomerase

Relieves strand on DNA strand on DNA to prevent unwinding of DNA

DNA Primase

Creates RNA strands complementary to the template strand

DNA Ligase

Attaches to the 5’ end of the strand to the 3’ end of an adjoining strand to make a continuous DNA strand from the fragments

Leading Strand

Continuous synthesis TOWARDS replication fork

Goes towards 3’ end of DNA

Transcription

Going from DNA to RNA

Translation

Going from RNA to Proteins

Lagging Strand

Individual fragments synthesized away from DNA

Faces away from replication fork

Has segments called Okazaki Fragments

Telomerase

Non-coding repetitive sequence found at the end of chromosomes

Acts as a buffer to protect protein coding genes

Shorten with replication

Limit replicative potential of cells —> prevents cancer, but may contribute to aging

Limitations of DNA Polymerase

1) Can’t unwind double-stranded DNA

2) Can’t start a chain, but can add a nucleotide to an existing nucleotide strand

3) Can only add nucleotides in the 5’ to 3’ direction

4) Can’t link existing DNA chains to each other

End Replication Problem

Chromosomes shorten during each replicative cycle due to lagging strand dynamics

Gap Junctions

Protein channels that connect adjacent cells

Small molecules can pass directly from cell-to-cell

Good for fast, unregulated communication

Gap Junction Example

Cardiac muscles ensuring synchronous heartbeats

Receptor

Protein that recognizes a specific signaling molecule and sends some signal within cell to change behavior