Upload
trevor-henry
View
37
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Take out your HW: Transcription wkst. Somewhere on a sheet of scratch paper or in your notes, TRANSCRIBE the following DNA sequence into mRNA: TAC AGT CCA GCG ATA ATT. Homework due tomorrow: Protein Synthesis wkst. AUG. UCA. GGU. CGC. UAU. UAA. - PowerPoint PPT Presentation
Citation preview
Take out your HW: Transcription wkstHomework due tomorrow:
Protein Synthesis wkst
Somewhere on a sheet of scratch paper or in Somewhere on a sheet of scratch paper or in your notes, TRANSCRIBE the following DNA your notes, TRANSCRIBE the following DNA sequence into mRNA:sequence into mRNA:
TAC AGT CCA GCG ATA ATTTAC AGT CCA GCG ATA ATTAUGAUG UCAUCA GGUGGU CGCCGC UAUUAU UAAUAA
TRANSCRIPTION & TRANSLATION: From DNA to Protein Chapter 11, Section 2
Think back to the information contained in your Think back to the information contained in your homework assignment:homework assignment:
1.1. What is produced when the process of What is produced when the process of transcriptiontranscription is complete? is complete?
2.2. What are 2 differences that were listed/shown What are 2 differences that were listed/shown between DNA and RNA?between DNA and RNA?
Genes & Proteins
• What is the function of a gene?
– codes for traits, inherited from parents
• Genes code for specific proteins– Proteins make up muscles, hair, tissues,
enzymes, & pigments
• Protein Synthesis = reading the DNA, forming RNA, using RNA to make the protein (DNA RNA Protein)– Occurs through the processes of
transcription and translation
RNA
• RNA is a nucleic acid (like DNA)
• Differs in structure from DNA:
DNA RNA
Number of Strands 2 1
Nucleotide Sugar Deoxyribose Ribose
Nitrogenous Base Pairs
Thymine(T), Adenine(A), Guanine (G), Cytosine (C)
Uracil (U), Adenine(A),
Guanine (G),
Cytosine (C)
Focusing on RNA
• There are 3 different types of RNA that you will need to know:– mRNA– rRNA– tRNA
Types of RNA• 1. Messenger RNA
(mRNA) – Carries genetic
“message” from DNA to the ribosomes in the cytosol
– “Read” by ribosomes to make proteins
– Contain codons
• 2. Ribosomal RNA (rRNA)– Part of the structure of ribosomes– Ribosome = protein and rRNA
• 3. Transfer RNA• Transfers amino acids to the ribosome to make
protein
Transcription: Getting the message out of the nucleus
• Transcription = enzymes make RNA by copying a portion of DNA in the nucleus
• If a DNA sequence is AATCCGGA, what is the complimentary RNA sequence?
• UUAGGCCU• The mRNA that gets sequenced is sent out of the
nucleus to help make protein
Genetic Code• Sequence of Nitrogenous Bases codes for a
specific Amino Acid that is connected to other amino acids to make a Protein
• Codon = the nitrogenous bases of 3 adjacent nucleotides in mRNA that code for– Start Signal (starts the protein making process)– 1 of 20 different amino acids (parts of a protein)– Stop Signal (stops the protein making process)
• Codons are like 3-letter words– Words contain meaning to us: CAT = – Codons contain meaning in the form of an amino acid CAU = Histidine
•An amino acid can be coded for by more than one codon•20 amino acids combine in different combinations to make various proteins
Translation: Going from the language of bases (AUGC) to proteins
• Translation = using the mRNA to make protein, reading the codons– Takes place at the ribosomes
• The mRNA is “read” in between the 2 sub-units of the ribosome
• tRNA carries the amino acid coded for by the mRNA codons and has an anticodon that pairs up with the mRNA codon– Codon (mRNA) and anticodon (tRNA) follow RNA
base-pairing rules
• Amino acids form peptide bonds between each other to create a long chain of amino acids
Transcription
Amino acids to protein
• Amino acid chains start to fold creating 3-dimensional structures
• Several of these 3-D structures combine to form a functional protein
• These proteins then carry out cellular functions