Section 1
1. Griffith showed that an injected bacteria strain that is harmless cannot harm an organism. Also, bacteria cannot withstand extremely high temperatures. Although, when you mix a heat killed bacteria with a harmless bacteria, or a rough colony, then the bacterias will trigger eachother into a deadly, living bacteria.
Avery and other cientists discovered that DNA is the nucleis acid that stores and transmits the genetic information from one generation of an organism to the next. And Hershey and Chase concluded that the genetic material of the bacteriophage was DNA, not protein.
2. Watson and Cricks model of DNA was a double helix, in which 2 strands were wound around each other.
3. There are 4 types of nitrogenous bases in DNA. Adenine and gaunine are known as purines, and the other two, cytosine and thymine are pyrimidines. Purines have 2 rings in heir structures, by pyrimidines have one ring.
4. Watson and Crick’s model shows that every DNA strand has base pairs, which explains Chargaff’s rules. So, [A] = [T] and [G] = [C]. In other words, for every adenine in a double-stranded DNA molecule, there had to be exactly on thymine molecule, and for each cytosince molecule, there had to be one quanine molecule.
5. Hershey and Chase grew viruses in cultures that contained radioactive phosphorus and radioactive sulfer so they could tell whether genes were made of protein, which contains no sulfer, or protein which contains almost no phosphorus.
section 2
1. In DNA replication, the DNA molecule separates into two strands, then produces 2 new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serces as a template, or model, for the new strand.
2. Eukaryotic chromosomes contain both DNA and protein, tightly packed together to form chromatin.Chromatin consists of DNA histones and together they create a nucleosome. These structures pack toether to form a thick fiber, which is shortened by a system of loops and coils.
3. To fit long DNA molecules in a eukaryoticcell the DNA must be folded into a space only one one-thousandth of its length. Eukaryotic chromosomes contain both DNA and protein, tightly packed together to form chromatin.Chromatin consists of DNA histones and together they create a nucleosome. These structures pack toether to form a thick fiber, which is shortened by a system of loops and coils.
4. DNA is coiled around histones and together with the chromosome the DNA creates a beadlike structure- a nucleosome. These pack with one another to form a thick fiber, which is shortened by a system of loops and coils.
5. DNA polymerase is the principal enzyme involved in DNA replication because it polymerizaes individual nucleotides to produce DNA.
6. The main difference between eukaryotes and prokaryotes in how they hold their DNA is the space. In prokaryotes they have much more space, but in eukayotes they have probably less than an inch.
section 3
1. The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA.
2. During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA.
3. During translation, the cell uses info froma messenger RNA to produce proteins.
4. The main differences between RNA and DNA are that the sugar in RNA is ribose instead of deoxyribose, RNA is generally single-stranded, and it contains uracil in place of thymine.
5. ACCGUCACG
section 4
1. A gene mutations result from changfes in a single gene. Chromosomal mutations involve changes in whole chromosomes.
2. Point mutations are mutations that affect one nucleotide in the DNA sequence.
3.
DNA: TAC GCA TGG AAT
mRNA: AUG CGU ACC UUA
Amino
Acid: Met-Arg-Thr-Leu
Substitution
DNA: TAC GTA TGG AAT
mRNA: AUG CAU ACC UUA
Amino
acid: Met-His-Thr-Leu
AND
DNA: TAC GCA TGG AAT
mRNA: AUG CGU ACC UUA
Amino
Acids: Met-Arg-Thr-Leu
Insertion
DNA: TAT CGC ATG GAA T
mRNA: AUA GCG UAC CUU A
Amino
acids: Ile- Ala-Tyr-Leu
4. The 4 types of chromosomal mustations are deletion involves the losss of alll or part of a chromosome, duplication, inwhich a seg ment of chromosome is repeated, inversion, when a chromosomes is oriented in the reverse of its usual direction, and translocation occurs when part of one chromosome breaks off a nd attaches to another, nonhomogous, chromosome.
5. A biologist can determine whether a mutation is present or not by taking a sample of the person’s blood and running a DNA test on it using instuments such as a light microscope, and depending on what section of the DNA is missing then you can tell what the mutation is.
section 5
1. The lac genes are turned off by repressors and turned on by the presence of lactose.
2. Most eukaryotic genes are contollled individually and have regulatory sequence that are much more complez than those of the lac operon.
3. A promoter is a binding site for RNA polymerase.
4. Regulating the expression is especially improtant in shaping the way a complex organism develops from a single fertizled cell.
5. In fruit flies a series of hox genes along a chromosome determines the basic structure of the flyu’s body. Mice have very similar genes on 4 different chromosomes. Although the fruit fly’s are located side by side in a single cluster, arranged in the exact order expressed int he body. Mice have a multi-row cluster of genes.
