How does DNA control cell activities?

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Transcript How does DNA control cell activities?

How does DNA control cell
Protein Production
• The sequence of nucleotides in DNA
contains instructions for producing
• What are proteins?
• Which cellular organelles are associated
with the production of proteins?
What are proteins?
• Polymers constructed from long chains of
amino acids.
– Peptide bonds join together amino acids.
• Proteins regulate cell functions.
• Comprise filaments in muscle tissue
• Enzymes control chemical reactions in a cell
– Breaking down glucose
– Forming spindle fibers in mitosis
How many types of nucleic
acids are found in your cells?
– Deoxyribonucleic Acid
– 5-Carbon Sugar = Deoxyribose
– Double-stranded
– Ribonucleic Acid
– 5-Carbon Sugar = Ribose
– Single-stranded
RNA-What does it do?
• Same nitrogenous bases as DNA…EXCEPT
thymine is replaced with URACIL
• Uracil pairs with Adenine
• Takes instructions from DNA and builds
proteins amino acid by amino acid.
How many types of RNA help
build proteins?
• mRNA
– Messenger RNA
– Copies instructions from DNA in nucleus
– Brings instructions from nucleus to the
cytoplasm to the ribosome
• Three nucleotide sequence that codes for a
specific amino acid
How many types of RNA help
build proteins?
• rRNA
– Ribosomal RNA
– Composes ribosomes
– Binds to mRNA and uses instructions to
assemble amino acids in the correct order
How many types of RNA help
build proteins?
• tRNA
– Transfer RNA
– Delivers amino acids to ribosome for protein
• Three-nucleotide sequence attached to amino acid.
• Complimentary to mRNA codon
Process of protein synthesis
Two Parts of Protein Synthesis
– Occurs in nucleus
– mRNA gets information from DNA and takes
out to ribosomes
– Occurs at ribosomes in cytoplasm
– Converts information in mRNA sequence into
a sequence of amino acids in a protein
Transcription Process
• Enzymes unzip DNA molecule in specific location
• Free RNA nucleotides form complimentary base
pairs with the nucleotides on the DNA strand
mRNA strand breaks away and DNA strand
mRNA strand leaves the nucleus and enters the
cytoplasm through nuclear pores
Translation Process
• For protein assembly, different amino
acids in cytoplasm must be delivered to
the ribosomes
• Each tRNA molecule attaches to a specific
amino acid
• tRNA ANTICODONS pair with
complimentary mRNA CODON
Translation Process
• Amino acids form peptide bonds with each
other to form long chains called
• This process continues until a STOP codon
is reached
Translation Process
• Then the amino acid chain breaks off and
twists into a complex 3D shape
• Different proteins = Different cell
structures and enzymes