Essay about Biology Notes

Submitted By Angiejarquin
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Chapter 2:
Uses of Radioactive Isotopes
Elements are arranged outside the nucleus of an atom- electron shells
First shell-maximum 2 electrons
Second, third, fourth….-8 electrons each
Atoms to Molecules
Ex: H+H=H2
H20, CO^2, etc.
Chemical Bonds
2 types of bonds
Ionic bonds: giving or accepting electrons. Weak bonding
Covalent bond: sharing electrons. Strong bonding,
Hydrogen bond
Ionic Bond
If an atom loose or gain electrons- the electrical charge will be changed
Charged atoms are called ions
Positive ion: when atom looses electrons, it becomes positive ion
Negative ions: atom gained electrons become negative ion
Covalent Bond
When atoms share electrons, thereby completing their valence shells
Strong bonding
Hydrogen Bonding
Hydrogen bonding links an already covalently bonded hydrogen atom with an electronegative atom
A solution is a homogenous mixture of two or more kinds of molecules, atoms, or ions.
The compound dissolved in solution is the solute.
The compound doing the dissolving is the solvent
Acids and Bases
An acid is any substance that yields hydrogen ions when put in aqueous solution
A base is any substance that accepts hydrogen ions in solution
Chemical or combination of chemicals that keeps pH within normal limits
Ex: pH of blood is about 7.4- maintained by buffer
Chapter 3:
Molecules contain both Carbon and Hydrogen atoms
The Biological Molecules (Four categories)
Nucleic acids
Organic Molecules
Polymers (complex molecules)
Are large molecules made with smaller molecules of monomers
Monomers: simpler molecules
Polymer: many monomers joined
Many functions:
Support, metabolism, transport, defense, regulation, motion
Amino Acids
Units of proteins are amino acids
Proteins are made of by amino acids
20 types of amino acids: human body uses 20 types of amino acids to make different proteins
The sequential arrangements of different amino acids determine the property of proteins. Example: T,I,M,E. TIME, EMIT, MITE.
Amino acids are linked into chains to polypeptide
Polypeptide chain folds up to from a protein
The defining characteristic of all lipids is that they don’t readily dissolve in water
All are insoluble in water
Fats and oils used for long term energy storage
Oil may help waterproof skin, hair, and feathers
Among the most important lipids are the triglycerides, composed of a glyceride and three fatty acids
Most of the fats that human beings consume are triglycerides
Are biological molecules that are combinations of lipids and proteins

Chapter 4: Cell’s as Life’s Fundamental Unit
Parts of a cell:
Plasma membrane (cell membrane)
Cytosol (fluid inside the cytoplasm)
Nucleus, a region of DNA
Types of Cells
Prokaryotic cells: no nucleus and no membrane bounded organelles
Ex: Bacteria and Archea
Eukaryotic cells: have nucleus and DNA is inside the nucleus
Ex: Fungi, Plants, Animals, etc.
Mitochondria and Energy
Mitochondria- organelles that function to extra energy from food and to transform this energy into ATP (a chemical form that the cell can use)
ATP- Adenosine Tri Phosphate
Most numerous in active cells
In humans, most mitochondria are inherited from the mother
Contain own DNA, separate from the nuclear DNA
Mitochondria first started off as bacteria cells
They invaded eukaryotic cells, and up becoming part of the modern eukaryotic cells
Endoplasmic Reticulum
A mass of membrane system in the cytosol interconnected channels within cell
There are two forms of ER:
Smooth ER: No ribosomes
Rough ER (RER): With ribosomes
RER: helps in the processing of proteins
SER: synthesis lipids, detoxification of harmful substances such as alcohol.
Golgi bodies
Stacks of flattened sacs
Receive proteins made by ER
Process proteins, sort and repackage and