University:
Sam Houston State University
Course:
BIOL 2413 | General Zoology
Academic year:

2022
Views:

68

Pages:

14
Author:

Clint W.

How are animal proteins made from DNA? In a process called “Protein Synthesis” The Big Picture!! What are the differences between DNA and mRNA? • DNA • Double stranded • Deoxyribose sugar • mRNA • Single stranded • Ribose sugar • Has uracil nucleotide in place of Thymine There are two processes to protein synthesis!! • Transcription DNA to mRNA (Messenger RNA). Takes place in the nucleus. • Translation mRNA to tRNA (Transfer RNA). Takes place in the ribosomes of the cytoplasm. Let’s see these two processes up close in steps!! What is “transcription?” • A part of the DNA double helix within the nucleus is unzipped, cut by enzymes, and then copied onto a new single strand, called mRNA. This process is called “transcription.” • Once the DNA is transcribed, the single strand moves from the nucleus to a ribosome in the cytoplasm of the cell. Thus the name, “messenger RNA.” Nitrogen Bases • You already learned that the nitrogen bases in DNA are: Adenine – Thymine Guanine – Cytosine • The Nitrogen bases in RNA are similar, but rather than Thymine, RNA contains a similar base called Uracil. Thus, the base pairs are: Adenine - Uracil Guanine - Cytosine • One strand of the DNA helix is used as a template to make “mRNA” (copy of the DNA section) during transcription. Let’s copy some DNA to mRNA!! 1. DNA strand ATCGGCATCATT 2. MRNA strand _ _ _ _ _ _ _ _ _ __ 3. DNA strand ATGAAGGCGAAA MRNA strand _ _ _ _ _ _ _ _ _ _ _ REMEMBER: in mRNA, Uracil replaces Thymine Answer!!! • DNA strand: ATCGGCATCATT • mRNA strand: UAGCCGUAGUAA • DNA strand: ATGAAGGCGAAA • mRNA strand: UACUUCCGCUUU Sample Question • A. • B. • C. • • • • UUGGCCGAUUGG TTGGCCGATTGC AACCGGCTAACC Which strand is ____ DNA STRAND 1 ____ DNA STRAND 2 ____ mRNA Answer! • A. • B. • C. • • • • UUGGCCGAUUGG TTGGCCGATTGC AACCGGCTAACC Which strand is __b or c__ DNA STRAND 1 __b or c__ DNA STRAND 2 __a__ mRNA