aim: what are the compounds important to living things? the physical and chemical properties of...
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Aim: What are the compounds important to living things?
The physical and chemical properties of water make it unique and necessary for living things
Water is necessary for all chemical reactions in living systems.
Water's Chemical Properties
Polar molecule
•sticky
•universal solvent
• pH of 7
Water's Physical Properties
• found in all three states of matter -- liquid, solid (ice), and gas (steam)
Water’s Physical Properties
• water's freezing point is 0 degrees on the Celsius scale
• water's boiling point is100 degrees Celsius
• high specific heat index
Physical Property of water
• high surface tension
Other important inorganic compounds found in living things include salt
body fluids contain salt
Halite
The Chemical Evolution occurred in H2O
The molecules we know today are descended from the first molecules that formed life on
Earth.
Earth’s Primordial Environment Present atmosphere First Molecules formed in organic soup
RNA was the first organic molecule to appear in the organic soup (ocean) of
modern Earth
• Read the article – take notes
• share with your group
What is RNA ?
Atom Element Compounds
Living things are made from organic compounds (C, H, O, N, S, P and other elements in minute amounts)
Organic CompoundsCarbohydrates – sugar, starches
Proteins – meat, fish, beans
Nucleic Acids – RNA, DNA
Lipids - fats
RNA is a polymer made up of four repeating subunits called nucleotides. Each nucleotide contains a sugar, a phosphate group and a nitrogenous base.
Aim: What is RNA?
Nucleotides in RNA are made up of a sugar, phosphate and base
The sugar in the nucleotide that makes up RNA is ribose
Types of RNA
• mRNA - carries a message
• tRNA – carries a code from the mRNA
• rRNA – structural RNA that makes up a ribosome
HW 6
• Make templates of the structures on the sheet with the Parts of RNA nucleotides
• Ribose + phosphoric acid – yellow• Uracil – blue• Cytosine – black• Adenine – red• Guanine – green• Cut out the pieces (4 ribose-phosphoric acid)
and one of each of the others.
Messenger RNA
Messenger RNA is transcribed in the nucleus.
Transfer RNA
The mRNA then enters the cytoplasm and attaches to a ribosome. Translation begins at AUG, the start codon. Each transfer RNA has an anticodon whose bases are complementary to a codon on the mRNA strand. The ribosome positions the start codon to attract its anticodon, which is part of the tRNA that binds methionine. The ribosome also binds the next codon and its anticodon.
mRNA Start codon
Ribosome
Methionine
Phenylalanine tRNALysine
Nucleus
Aim: What is the Structure of mRNA ?Section 12-3
mRNA
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