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89 terms

Chemistry Of Life - Biology

topic 3 chemistry of life
Most frequently occurring elements in living things:
Carbon, Hydrogen, Oxygen, Nitrogen
Organisms require a small amount of other elements:
Sulfure, Calcium, Phosphate, Iron, Sodium
What does sulfur (s) do
Makes amino acids which create proteins
What is the use of calcium (ca)
Strong bones, acts as a messenger
What is Phosphate (p) needed for
To create ATP + DNA
What is the use of Iron (fe)
Needed for haemoglobin (which carries oxygen)
What is the structure of water
Polar molecule, Hydrogen Bonding
What is a polar molecule made up of
Negative oxygen end + Positive hydrogen end
How does hydrogen bonding occur
Between the hydrogen of one water molecule and the oxygen of another water molecule
What are the properties of water
Coolant, Transport, Habitat
Define water as a coolant:
·lots of energy required to heat
·when water evaporates energy is used -> cools organism
Examples of water as a coolant
Sweating, Panting, Transpiration
Define water as a transport
·Water is polar, universal solvent (liquid that dissolves solutes)
·Dissolves many organic and inorganic substances
·Movement of water carries substances around organism
Examples of water in transport
Xylem, Phloem, Adhesion, Cohesion
Explain Xylem
Nutrients from roots to tree
Explain Phloem
Nutrients from tree to roots
Explain Adhesion
Two different substances attaching
Explain Cohesion
The same substances attaching
Define water as a habitat
Water is transparent
Allows light through for photosynthetic organisms
Organisms live in or on water because of surface tension
Contains dissolved gases
Aquatic organisms survive under ice at surface
What is surface tension
Organic compounds
Compounds found (built) in living things (organisms
Inorganic compounds
NOT found in living organisms
Major molecules
Amino acids, Glucose, Ribose, Fatty acids
3 types of saccharides
Monosaccharides, Dissacharides, Polysacharides
Examples of Monosaccharides
Glucose, Fructose, Galactose
Examples of Dissacharides
Maltose, Lactose, Sucrose
Examples of Polysaccharides
Starch, Glycogen, Cellulose
Which saccharides are in Animals
Glucose, Lactose, Gylcogen
The role of glucose in animals
Carried by blood to transport energy to cells throughout the body
The role of lactose in animals
The sugar in milk provides energy to young mammals until they are weaned
What is the role of glycogen in animals
Used as a short-term energy and is stored in liver and muscles
Which saccharides are in Plants
Fructose, Sucrose, Cellulose
What is the role of Fructose in plants
Used to make fruits sweet tasting, attracting animals to disperse seeds in the fruit
What is the role of Sucrose in plants
Carried by phloem to transport energy to cells throughout the plant
What is the role of Cellulose in plants
Used to make strong fibers that are used to construct the plant cell wall
Hydrolysis reaction is adding:
What is used up during hydrolysis reactions
Water Molecules
What is the reverse of condensation reactions
Hydrolysis reactions
Polypeptide + Water =
Dipeptides or amino acids
Polyssacharides + Water =
disaccharides or monosaccharides
Glycerides + Water =
Fatty acids + gylcerol
Function of lipids
Energy storage,Thermal (heat) insulation, Bouyancy
Function of energy storage in lipids
Energy storage in the form of fat in humans and oil in plants
Function of thermal insulation in lipids
A layer of fat under the skin reduces heat loss
Function of buoyancy in lipids
Lipids are less dense than water so help animals to float
What contains more energy per gram: carbohydrates or lipds
What kind of energy storage are lipids typically used for
Long term storage
What kind of energy storage are carbohydrates typically used for
Short term storage
Are lipids insoluble or soluble
Lipids are insoluble so they dont cause problems with:
Osmosis in cells
What is more easily digested carbohydrates or lipids
Carbohydrates can be easily digested therefore:
Energy stored can be released more rapidly
Are carbohydrates soluble or insoluble
Carbohydrates are soluble therefore
easier to transport to and from the store
3 parts to a DNA nucleotide
Sugar, Base, Phosphate
3 bases in DNA nucleotide
Adenine (A) Cytosine (C) Guanine (G) Thymine (T)
How are DNA nucleotides linked
by covalent bonds into a single strand
Where does the covalent bond occur
Between deoxyribose and phosphate group
DNA double helix is formed using
Complimentary base pairing and hydrogen bonds
Adenine is paired with
Cytosine is paired with
How many stages are there in the process of DNA replication
Stage 1 of DNA replication
Double helix unwinds and separates into strands (because of breaking of hydrogen bonds)
Helicase (enzyme) separates strands by breaking bonds
Stage 2 of DNA replication
Single strand act as templates for new strands
Free nucleotides are present for building
Bases of these nucleotides form hydrogen bonds with bases of parent strand
Nucleotides are linked up to form new strand
DNA polymerase is the enzyme used to create new complimentary strands
Stage 3 of DNA replication
Daughter DNA molecules each rewind into a double helix
Complementary base pairing allows
for conservation of the base sequence of DNA
What does semi-conservative mean
Each molecule is formed by replication
Consist of one NEW strand + one OLD strand conserved from parent DNA molecule
How many strands in DNA
2 strands
How many strands in RNA
Bases in RNA nucleotide
Adenine (A)
Cytosine (C)
Guanine (G)
Uracil (U)
Sugar used in DNA
Sugar used in RNA
Why do we make mRNA
Messenger to go into the cytoplasm and make proteins
What is transcription
Process of making mRNA
What does tRNA mean
Transfer RNA
What does rRNA mean
Ribosomal RNA
RNA is ? stranded
What is the point of transcription
DNA is an important molecule -> dont want to damage it
RNA ? does everything in transcription
RNA Polymerase
Steps of transcription
RNA Polymerase bind to a site called the 'promoter' on DNA
DNA strand separated by RNA polymerase on specific part of gene to be transcripted
RNA nucleotides pair with complementary bases on one strand of DNA only
RNA polymerase forms covalent bonds between nucleotides
RNA seperates from DNA and double helix forms
What is translation
Process of protein production using mRNA as a guide
Genetic code:
'translation dictionary' that enables cells to convert base sequences on the mRNA into an amino acid sequence
What is a codon
Sequence of 3 bases on the mRNA
What is tRNA
Transfer RNA that carried amino acids
Where does translation take place:
Where are Ribosomes found:
In Cytoplams, outside the Nucleus
Each ribosome has a large and small ?:
Ribosomes make->
Process of translation:
mRNA binds to small subunit of ribosome (5'->3') direction
tRNA molecules present, each one carrying specific amino acid corresponding to anti-codon
tRNA binds to ribosome at the site where its anti-codon matches the codon on the mRNA
2 tRNA bind at once, 1st transfers