DNA Replication. Vocabulary: Replication - Synthesis of an identical copy of a DNA strand. http://www.lewport.wnyric.org/jwanamaker/animations/DNA%20Lecture.html. In which cell organelle is DNA replicated?. Nucleus. When does DNA cell replication occur?. Before a cell divides
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Replication - Synthesis of an identical copy of a DNA strand.
When does DNA cell replication occur?
When DNA replicates, it results in __________ of the number of chromosomes in a cell?
Is the blueprint of life (has the instructions for making an organism) established by James Watson and Francis Crick
-codes for your genes
-shape of a double helix
-made of repeating subunits called nucleotides
Nucleotide - consists of a sugar, phosphate and a base
Adenine, Thymine, , Guanine, Cytosine or A, T, G, C
Nucleotides pair in a specific way
- called the Base-Pair Rule
Adenine pairs to Thymine
Guainine pairs to Cytosine
If you know the sequence of base on one strand, you can predict the sequence on the other strand. (Base ? ___________)
What is the sequence of nitrogen bases on the left side of the DNA molecule below?
Predict the sequence of nitrogen bases on the right side of the DNA molecule below?
If one strand of DNA has the base sequence C A T G A G C G C G A T , what will be the sequence on the other strand? > GTA CTC GCG CTA
How DNA replicates
Understanding this goes a long way to explaining how nuclei divide in the process of mitosis , which results in identical copies of chromosomes being transferred during ordinary cell division.Before a cell divides, its nucleus must divide. But before that happens, the chromosomes must have become double. So the first stage is that DNA which the chromosomes contain must replicate , i.e. become double, by making copies of itself.The 2 strands of the DNA double helix can separate, under the influence of special enzymes in the nucleus, but each half remains attached along its length, like the 2 sections of a zip, because the sides of the strands are strongly joined.In the diagrams below, write in the letters for the various bases (using the first few as a key). This should help you understand the results of the process.
Each strand then acts as a basis for rebuilding the missing other strand from which it has been separated. It is said that each strand forms a template on which it reforms its complementary strand. Enzymes within the nucleus match the appropriate base, which is already attached to strand side subunits, so that A fits against T, G against C, T against A and C against G, according to shape.Other possibilities are not allowed, so the copying process is accurate in the vast majority of cases.The result is that one double strand is converted into two identical double strands.It is interesting to note that each "new" double strand is in fact half composed of a section of the previous DNA molecule, together with a completely new section built up from individual bases.
Because of this, it is called semi-conservative replication.
HW Read Page 413-416 and answer pg 416
#7,12, 13,14 15 Q&A on LL
Genes are areas on the DNA molecule that code for the synthesis of specific proteins.
What is The Genetic Code?
It is three adjacent nucleotides (“letters”) in mRNA that specify an amino acid in a polypeptide, (_________) molecule.
Is a process whereby DNA encodes for the production of amino acids and proteins.
This process can be divided into two parts:1. Transcription 2. Translation
Transcription - Synthesis of mRNA
Translation - Synthesis of polypeptide from amino acids.
Codon - Base triplet on mRNA.
Anticodon - Complementary triplet on tRNA.
Polypeptide - ______ molecule
how does the information (genetic codes) within the DNA molecule get to the ribosome’s where proteins are synthesized?
An intermediate molecule is needed.
RNA is that molecule.It is single stranded and thus is smaller than DNA & able to leave the nucleus through the nuclear pores and carry the codes to the ribosome
Uracil (U)* instead of Thymine (T)
Uracil (U)* instead of Thymine (T) in the RNA
1. Transcription 2. Translation
One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize a messenger RNA (mRNA).
The mRNA then migrates from the nucleus to the ribosome.
The DNA molecule unzips /opens up on one side only and the base sequence is transcribed into a complementary sequence of bases forming a mRNA molecule. Remember Uracil (U)* instead of Thymine (T)
What will the sequence of bases in the mRNA?
DNA Sequence (left side) __A C A____G G A______C G A______
mRNA Sequence _________________________________________
AUG = Start & Methionine Amino Acid
UAA = Stop
- What is it?
The coded information flows from the DNA to the ribosome via the mRNA and then tRNA brings the corresponding amino acid.
Where does it take place?
Steps in Translation
(1) Initiation The ribosome binds to the mRNA at the start codon (_____) that is recognized only by the initiator tRNA.
Which cell organelle controls the manufacture of proteins in the ribosome?
What is in the nucleus contains the information for protein synthesis
There are twenty amino acids required for human life to exist. Adults have eight essential amino acids that they cannot synthesize. The other twelve can be produced within our bodies.
Essential amino acidshistidine, isoleucine, leucine, lysine,
methionine, phenylalanine, threonine, tryptophan, and valine.
What in the nucleus contains the codes for protein synthesis?
Answer: The DNA