Lecture 2: Review of Basic Biology

Question 1

Cell Theory

Answer 1

• Cells are an organism’s basic structure and function
• All organisms are made of cells
• All cells come from pre-existing cells

Question 2

Three Domain Classification

Answer 2

Bacteria (P), Archaea (P), and Eukarya (E)

Question 3

Genome

Answer 3

• Complete set of DNA in an organism’s nucleus and mitochondria (and chloroplast)
• nucleus contains most of the cell’s DNA while additional genes are located in the mitochondria and chloroplasts of eukaryotic cells

Question 4

Genomics

Answer 4

Large-scale study of sets of genomes between species

Question 5

Basic Feature of Cells

Answer 5

• Enclosed by plasma membrane which regulates the passage of materials between the cell and surroundings
• Cytosol
• DNA as genetic information
• RIbosomes that make protein

Question 6

Human Genome Project

Answer 6

Sequencing of the entire 3 billion subunits of the human genome. Identified all human genes and made them accessible for further studies.
Founded by Craig Venter and Francis Collins

Question 7

Chromatin

Answer 7

A complex of DNA and proteins, when cells are not dividing, chromatin exists in dispersed form. In eukaryotes, during cell division chromatin condenses to form discrete chromosomes.

Question 8

Gene

Answer 8

• Unit of inheritance that is a sequence of nucleotides on DNA that provide cells with the information needed to produce a specific protein
• Responsible for organisms’ traits (inherited physical appearance), some traits are controlled by a single gene while some are by multiple
• 23 Chromosomes from mom and 23 from dad, Haploid (n)-23 and diploid (2n)-46, each chromosome contains hundreds- thousands of genes

Question 9

Oswald Avery

Answer 9

Discovered isolation of pure DNA

Question 10

James Watson and Francis Crick

Answer 10

Proposed double-helical model for the structure of DNA
- model demonstrated how the molecule can carry information to serve as a template for its duplication and for the synthesis of protein

Question 11

Pyrimidine

Answer 11

Bases have a 6-member ring with 4 carbons and 2 nitrogen
example: Cytosine, Uralic (R), THymine (D)

Question 12

Purine

Answer 12

Bases that have a 9 member double ring system with 4 nitrogen and five carbon
example: Adenine and Guanine

Question 13

Nucleotides

Answer 13

Building blocks (monomers) of DNA
-3 main chemical groups: phosphate, pentose sugar, and a nitrogenous base
- The four nucleotides differ by their nitrogenous bases

Question 14

DNA

Answer 14

• consists of 2 anti-parallel strands that are in a double helix
• polarity between the strands with a free phosphate group on 5’ and a free hydroxyl group on 3’ end
• paired strands stabilized by H-Bonds that are weak and form when + charge attracted to negative charge (AT and GC)

Question 15

Origins of Replication

Answer 15

Regions where two DNA strands are separated, opening up a replication bubble

Question 16

Replication fork

Answer 16

Where new DNA strands elongate

Question 17

Helicases

Answer 17

Enzymes that untwist the double helix at the replication fork

Question 18

Single-strand binding (SSB) proteins

Answer 18

Bind and stabilize the unwound DNA until it can be used as a template for DNA replication

Question 19

Gyrase

Answer 19

Corrects over winding ahead of replication forks by breaking, swiveling, and rejoining DNA strands

Question 20

DNA Polymerase III

Answer 20

Catalyzes the addition of nucleotides to generate new polynucleotide strands of DNA

Question 21

RNA Primer

Answer 21

Generated by an enzyme called primase

Question 22

Primase

Answer 22

Adds RNA nucleotides one at a time at the replication fork, using parental DNA as a template to generate an RNA primer

Question 23

DNA Polymerase I

Answer 23

Removes RNA primer and replaced with DNA nucleotides

Question 24

DNA ligase

Answer 24

Joins sugar-phosphate backbones of all Okazaki fragments together into a continuous DNA

Question 25

Telomeres

Answer 25

-Repetitive nucleotide sequences at the end of eukaryotic chromosomes (TTAGGG)
-they do not contain genes instead they protect genes from being eroded through multiple rounds of DNA replication

Question 26

Telomerase

Answer 26

• Keeps telomeres from being eroded
• Telemorerase activity declines after birth and are highly active in most cancers