Chapter 4: DNA and Gene Expression

1. What is DNA?

molecular script of life

2. What is DNA made up of?

two long strands, nucleotides, wound together in a double helix structure

3. What shape is DNA?

Double helix

4. What is each nucleotide made up of?

A phosphate group, a deoxyribose sugar, and a nitrogenous base

5. What is the backbone of DNA?

a sugar-phosphate backbone

6. How are the rings of the ladder connected together?

hydrogen bonds

7. What are the four nitrogen bases?

adenine, guanine, cytosine, thymine

8. How do the nitrogenous bases of DNA pair?

A-T, C-G

9. What do the sequence of bases code?

Proteins

10. How does Biotechnology use DNA's stability and reproducibility?

PCR, gene sequencing, and genetic engineering

11. What does understanding the structure of DNA allow?

Foundations for modern biotech and genetic medicine

12. When does DNA replication occur?

S phase

13. What is semiconservative replication?

contain a parental strand and a daughter strand

14. How does the DNA double helix unwind?

helicase (enzymes)

15. What is the replication fork?

where DNA is opening

16. What is the leading strand?

one of the strands created continously

17. What is the lagging strand?

one of the strands creates in fragments

18. What type of DNA does bacteria have?

singular, circular and double-stranded DNA

19. What is DNA polymerase?

enzyme that separates DNA strands and builds new complementary strands

What is the Origin Recognition Complex?

What is Helicase?

What is the purpose of the template DNA?

What is the Replication bubble?

What is the replication fork?

where DNA is opening

What are topoisomerases?

prevent DNA from unwinding ahead of the fork

What are single-strand binding proteins?

Bind to unpaired DNA proteins to keep them from reattaching, stabilize the open replication fork

What are RNA primers?

short RNA sequences synthesized to start DNA synthesis

What is primase?

enzyme that synthesizes RNA primers on both strands

What are Okazaki fragments?

short stretches of newly synthesized DNA joined later in a continous strand

What is DNA ligase?

enzyme that joins Okazaki fragments, final step in ensuring a complete strand.

What are histone proteins?

 What are histones?

histone complex after DNA loops around them

What are nucleosomes?

basic unit of chromatin consisting of DNA wrapped around histones and resembles beads on a string.

What is chromatin?

entire DNA protein complex visible in the nucleus

What are euchromatin?

loosely packed and active

 What are heterochromatin?

tightly packed and inactive

Who discovered transformation?

Frederick Griffith

When was transformation discovered?

1928

What was the end conclusion of DNA transformation?

DNA is the molecule for heredity

What is transcription?

creating a complementary RNA molecule from a DNA template

What is MRNA?

single strand RNA copies DNA that carries genetic info to ribosomes

What is a ribose phosphate backbone?

RNA’s sugar phosphate structure

What is a codon?

sequence of 3 RNA bases that code for a specific amino acid

What is a polypeptide?

chain of amino acids linked by peptide bonds folds into functional protein

 What is an enzyme?

biological catalyst formed from the polypeptide. Speeds up specific chemical reactions

What is the central dogma of molecular biology?

DNA→ mRNA→Protein→Trait