DNA
And RNA
By
Naomi Keddy
Heredity: Is the
passing on of features from parents to offspring by means of genes.
Gene:
Is
a section of DNA that causes the production of a protein.
Gene
expression: Is the way in which the genetic information in a
gene is decoded in the cell and used to make protein.
Characteristics:
Are
traits or features that are inherited genetically.
Structure
of DNA:
DNA stands for deoxyribonucleic
acid. DNA is a double stranded molecule made up of elongated chains of
sub-units called nucleotides. DNA contains four chemicals called base pairs
which are:
-Adenine (A)
-Thymine (T)
-Guanine (G)
-Cytosine (C)
A joins with T (2 hydrogen bonds)
and G joins with C (3 hydrogen bonds).
Each nucleotide is made up of a
phosphate, a sugar and a base.
DNA
Replication:
-Different base pairs join
together A-T and G-C
-The Double helix unwinds
-An Enzyme breaks the bonds
between the base pairs.
-The two strands of the double
helix separate
-The new copies of bases attach
to the exposed complementary bases.
-The DNA molecule acts as mould
or template for the new DNA that is formed.
-The new double strand rewinds to
form a double helix.
DNA
profiling:
-The DNA is released from the
cells
-DNA is cut into fragments of
different length.
-Fragments are separated
according size.
Patterns produced by the
fragments are compared
Examples of DNA profiling
are forensic scientists and Paternity Disputes
RNA
Structure:
RNA stands for ribonucleic acid.
RNA is singled stranded. RNA consists of four chemical bases which are
-Adenine (A)
-Uracil (U)
-Guanine (G)
-Cytosine (C)
A joins with U instead of T and G
joins with C
Difference
between DNA and RNA:
-DNA contains the sugar
deoxyribose and RNA contains the sugar Ribose
-DNA contains the bases A, t, G
and C and RNA contains the base A, U, G and C
-DNA is a double helix strand and
RNA is singled stranded.
Protein
synthesis:
Transcription:
-The DNA unwinds and the two
strands separate. Enzymes are involved in this process.
-RNA bases in the cytoplasm moves
across the nuclear membrane.
-RNA bases will match up with the
complementary bases.
-RNA enzyme polymerase causes RNA
bases to join together.
Translation:
-mRNA moves from the nucleus to
the cytoplasm.
-Ribosomes are made up of
ribosomal RNA and protein
-mRNA strands form weak bonds
-In a ribosome will be the site
of protein synthesis
-tRNA molecules attracted to the
mRNA
-tRNA is complementary to mRNA
-A start codon begins the process
of translation.
- tRNA’s attach to the mRNA two at a time. Carrying
their precise amino acids to the ribosome.
- tRNA molecules leave the
ribosome leaving their amino acids.
-tRNA molecules continue to bind
with the mRNA until a stop codon is reached.
-The amino acid sequence of the
new protein is now complete.
when was this published?
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