DNA RNA PROTEIN

DNA

• 1. What 2 components make up the DNA backbone?

• 2. What 3 components make up a nucleotide?

• 3. What are the rungs of the ladder?

Base Pairing

• A – T• G – C• 4. Write the complementary strand for this

sequence.– CGC TTA ATG CGA TGA

Question

• 5. Suppose a section of DNA has a total of 100 nucleotides in both strands. Of these, 20 have adenine bases. How many of those 100 nucleotides have the following:– Thymine (T) bases:– Cytosine (C) bases:– Guanine (G) bases:

Replication

• 6. Describe where each strand of DNA from parent molecule ends up.

• 7. What is the main enzyme involved in this process?

Gene Expression

• 8. Put the symbols in the correct order:

DNADNA

RNA RNA

PROTEINPROTEIN

TRANSCRIPTION

TRANSCRIPTIONTRANSLATION

TRANSLATION

REPLICATIONREPLICATION

Transcription

• RNA polymerase converts DNA to mRNA• A-U• G-C• 9. Convert the following DNA strand to RNA– CGA AAA TGC ATT

Translation

• mRNA encoded into amino acids

Mutations

• Mutations: mistakes in DNA replication• Point mutations– Substitution– Deletion– Insertion

• Chromosomal mutations– Inversions – Translocations

Mutation Examples

SUBSTITUTIONJEN PET THE WET DOG

Sub first E for AJAN PET THE WET DOG

INSERTIONInsert Z in first word

JZE NPE TTH EWE TDO10. Which is worse for the cell, a substitution or

insertion?

Mutation Examples

INVERSIONSJEN PET THE WET DOG

Flip “THE WET” and put it back in JEN PET TEW EHT DOG

TRANSLOCATIONJEN PET THE WET DOG DAN RAN ALL DAY

JEN / PET THE WET DOG DAN RAN / ALL DAYJEN / ALL DAY DAN RAN / PET THE WET DOG

Causes and Effects of Mutations

• Cause:– Radiation– Chemicals– Excessive heat

• Effects:– Somatic cells: only affects organism – Gametic cells: can be passed to offspring– Some are actually beneficial – Important source of variation

Practice Questions

11. DNA molecules must unwind and then separate for replication and expression. Which of these happens when the DNA molecule comes apart?

a. The weak bonds within the sugar-phosphate backbone are broken. b. The strong bonds within the sugar-phosphate backbone are broken.c. The weak bonds between the nitrogenous base pairs are broken. e. The strong bonds between the nitrogenous base pairs are broken.

Practice Questions

12. When the genes encoded in deoxyribonucleic acid are expressed, what type of molecule is produced?

a. DNAb. carbohydratec. phospholipidb. protein

Practice Questions

13. Which of the following gives the most accurate description of the gene expression process?

a. DNA tRNA mRNA amino acid protein

b. DNA anticodon codon tRNA amino acid

c. DNA mRNA tRNA amino acid protein

d. DNA mRNA tRNA codon amino acid

Practice Questions

14. A double-stranded segment of DNA is 50 nucleotides long along each strand. Thirty of the bases are adenine. How many of the bases are cytosine?

a. 20b. 30c. 50d. 80

Practice Questions15. Suppose that a point mutation inserts a thymine base

into a DNA strand as shown blow. T

TAA GGT ACG CAT

Which represents the DNA strand that is complementary to the first 12 bases of the mutated strand?

a. AAT CCA TAG CGTb. AUU CCA UAG CGU c. ATT CCA TGC GTAd AUU CCA UGC GUA