Download Journey into DNA - ANSWERS

JOURNEY INTO DNA
ANSWERS
Go to http://www.pbs.org/wgbh/nova/photo51/jour-flash.html
As you journey into DNA, answer these questions in your composition notebook:
1) About how many cells are in the human body? 100,000,000,000,000
2) In what cells is the human genome located? Every cell in the body except red blood cells
3) What makes red blood cells exceptions to all other cells? No nucleus, no nuclear DNA
4) What does it mean for a cell to be specialized? Perform different functions (nerve, blood, liver...)
5) How does an undifferentiated embryonic cell become specialized? Turning on/off different sections of DNA
6) Why is the cell’s nucleus called its control center? Regulates growth, metabolism, reproduction, stores DNA
7) Where are chromosomes located? In the cell nucleus
8) How many sets of chromosomes make up the human genome? 2
9) How many pairs of chromosomes are there? 23
10) Where do the sets come from? Two parents
11) How do we understand 97% of the genome? Sequences that don’t code for protein, have no known function
12) In this tutorial, the genome is said to have how many genes? An estimated 70,000
13) In the film, how many genes were said to make up the human genome? 26,000
14) Speculate about the differences in the numbers. The tutorial was made before the genome was mapped
15) When a chromosome looks like an X, what’s about to happen? They’re compacted, about to divide
16) This cell division is called? Mitosis
17) How is it different from meiosis? Mitosis makes exact copies; meiosis divides gametes into half
18) What are chromosomes bands made of? Genes
19) Why, at this cell stage, are there identical chromosome pairs? So mitosis makes exact copies
20) Where are genes located? In bands on chromosomes
21) In addition to determining specific traits, what else to genes do? Control how cells grow and interact
22) What are genes made of? DNA; nucleotide bases (btwn 100-million) and protein
23) If stretched out straight, what is the linear length of DNA in the human genome? About 6 feet
24) How does it all fit into the nucleus of every cell? Bends and loops the DNA
25) What’s the name of the ‘spring coils’ in a gene? Chromatin
26) What is chromatin made of? Protein
27) DNA has a slight positive or negative charge? Negative
28) What’s the name of the protein ‘discs’ that DNA is wrapped around? Histones
29) Why wasn’t Rosalind Franklin also awarded the Nobel Prize along with Watson and Crick? She died
30) In order to see ‘naked’ DNA unobscured by chromatin, what has to be removed? Protein molecules
31) Name the four bases in DNA. Guanine, cytosine, thymine, adenine
32) What is a rung on the DNA ladder made of? Two bases
33) Thymine pairs with… Adenine
34) Guanine pairs with… Cytosine
35) The sides of the DNA ladder, which the bases attach to, are made of what molecules? Sugar and phosphate
36) What are these molecules, together with the attached bases, called? Nucleotides
37) About how many atoms are each nucleotide molecule made up of? +/- 30 atoms
38) Name the 5 types or elements of atoms. Hydrogen, Carbon, Oxygen, Nitrogen, Phosphorus
39) There are approximately how many base pairs in the human genome? About 3 billion
40) While we now know the sequence of DNA bases that make up the human genome,
what don’t we know? What all the base sequences do…