Bio Test 3 Modules 9-12
How many times has DNA replication taken place in each of us (since we were zygotes)?
"Countless bazillions"
How is the human protein mass-produced by transformed bacteria?
The bacteria rapidly multiplies and carries out protein synthesis on the gene of interest.
What in general occurs during translation?
The information in mRNA is used to make protein
With DNA fingerprinting, investigators may state that the odds against a suspect being innocent are 1 in 33 billion. Explain where that type of statistic comes from.
The product of all 13 possibilities
Why is transformation necessary?
to add the gene of interest back into the bacteria so it can reproduce.
What are the two parts of protein synthesis?
transcription and translation
What does it mean that the genetic code has redundancy?
There are several codons for most amino acids
What chromosomal abnormality is present in individuals with Down Syndrome?
There is an extra chromosome 21. Trisomy 21. 47 chromosomes per body cell.
What is the function of the DNA polymerases during DNA replication?
They are the "hook-em up" enzymes and the "proofreading" enzymes.
What are the helicases and what is their function during DNA replication?
They are the "unzipper" enzymes
Why are plasmids a valuable tool in biotech work?
They can be taken out of bacteria cells, modified, and put into other bacteria cells.
What do restriction enzymes do?
They cut DNA in a very predictable way
What is believed to be the natural function of restriction enzymes?
They cut up the DNA of invading viruses
What is meant by a sex-linked (X-linked) condition?
They're expressed differently by males and females
A mutation of which base codon is least likely to affect the amino acid coded for?
Third base mutation; because it only moves it up or down in the box and because of redundancy it may not matter.
Where does each part of protein synthesis occur?
Transcription in nucleus Translation in cytosol
In the abbreviation tRNA, what does the "t" stand for?
Transfer
What is a plasmid?
Very small circles of DNA also found only in bacteria
When is transcription of a particular gene complete?
When the enzymes reach the end of the gene
What is the (sex chromosome) genotype of individuals with Turner syndrome? What are two symptoms of Turner syndrome?
XO; in general, they're short and covered in brown spots called nevi
What is the (sex chromosome) genotype of individuals with Klinefelter Syndrome? What are two symptoms of Klinefelter Syndrome?
XXY; in general people have female features, dysfunctional testicles, and a tall stature
Is DNA replication taking place in our bodies right now? If so,where?
Yes, in our bone marrow.
what is meant by mutation?
a permanent alteration of a DNA base sequence
How many different human DNA segments are used in modern forensic DNA typing?
13
How many genes does an X chromosome have?
1500
During what decade was the DNA code deciphered?
1960s
When was PCR invented?
1983
In females, how many (of the four) daughter cells become egg cells? What happens to the others? What are they called?
1; the rest are discarded; polar bodies
During translation, how many mRNA codons are "read" at a time at a ribosome?
2
what is meant by recombinant DNA?
2 or more segment of DNA combined by humans through a process not found in nature
In males, what is the rate of sperm production?
250 million per day
in the genetic code, how many codons (and genetic) are "stop codons"
3
In males, how long does it take to manufacture a sperm cell?
3 weeks
How many DNA letters code for one amino acid? What is this sequence of letters called?
3; codon
In females, what is the rate of egg production (per lifetime)?
400 eggs/ lifetime
In general, what is the chance of a human couple having a male child? A female? Why is this?
50/50 (Punnett Square showing XX and XY)
how many codons (and anticodons) actually code for an amino acid?
61
How many different codons (and anticodons) are there?
64
How many genes does a Y chromosome have?
78
How often does Down Syndrome result from an extra chromosome in the egg cell? Sperm cell?
90% in eggs 10% in sperm
What specific mutation resulted in sickle cell anemia?
A CIT became a CAT
what is meant by transformation ( in the context of biotechnology)?
A cells incorporation of genetic material from outside its boundary.
What in general occurs during transcription?
A copy is made of one DNA gene forming one messenger RNA molecule.
How many ribosomes "grab" each mRNA molecule?
A lot
What is a base substitution mutation?
A single replacement of one nucleotide for another Correct DNA codon: Mutation codon: CIT CAT
Why are sticky ends considered valuable by those working with DNA?
Because they can function like puzzle pieces when joining segments of DNA
In females, when does meiosis for all eggs begin?
Before the birth of the female; about 2 months before birth
Worldwide for humans, are there more baby girls born each year or more baby boys? Explain why.
Boys; the Y chromosome is smaller and lighter giving sperm cells carrying a Y chromosome a slight advantage; about 5% more often worldwide
What is BamHI's recognition sequence?
CGATCC GCTAGG
What is meant by somatic cells?
Cells that do not become egg and sperm
How do researchers determine the actual length of DNA fragments in the various lines of a gel?
Comparison with the standard mix.
what is a base deletion mutation?
Correct DNA sequence: ATG CAT GCA TGC Mutated: ATG CTG CAT GC... The A in the second codon got deleted
What causes mutations?
DNA damage Mistakes in DNA replication
Which enzymes "edit" mistakes made during DNA replication?
DNA polymerases
What natural cellular process does PCR accomplish in a machine? (Hint: Cells do it during interphase.)
DNA replication
before biotechnology, where was HGH obtained for those unable to produce it on their own?
Dead human bodies
which type of mutation would have the greatest effect on the resulting protein?
Deletion Mutations
When does DNA replication occur during the cell cycle?
During interphase
When did restriction enzymes come into use?
Early 1970s
Why does everyone (except identical twins) have different DNA fingerprints?
Everyone has different DNA, meaning everyone's DNA will "chop" differently.
In genera;, what happens when nondisjunction occurs during meiosis?
Failure during meiosis of chromosomes or chromatids to seperate properly.
What determines the sex of an individual for humans?
Female: XX Male: XY
In females, what is required for the (total) completion of meiosis?
Fertilization
A mutation of which type of cell can be inherited?
Germ-line cell
How "new" is each new DNA molecule?
Half new
what important protein is affected by sickle cell anemia?
Hemoglobin
Where is it normally produced?
In the human pituitary gland
What is the reason that some traits are "sex-linked"?
Involve genes on the X chromosome that are not on the Y chromosome
Where is mRNA before transcription?
It has not been created yet.
After DNA replication has taken place, where is the original DNA molecule?
It is half of the new helix
What is the function of HGH?
It promotes normal growth
Who invented PCR?
Kary Mullis
What is biotechnology?
Manipulation of DNA for various purposes.
Are DNA fragments positive or negative? How do you know?
Negative; they move towards the positively charged side (run towards red).
Will all base substitution mutations affect the resulting amino acid? Why or why not?
No; because of the property of redundancy
How many chromosomes does each bacterium have?
One
How many sides of a DNA molecule are transcribed?
One
What does DNA replication accomplish in terms of chromosomes?
One DNA molecule becomes 2 identical DNA molecules.
Describe the bacterial chromosome
One large circle
Who is the "needed human protein" needed by?
People who cannot produce it on their own
In an 8-year-old female, at what stage of meiosis are all her eggs-to-be?
Prophase I
What does each gene directly code for?
Protein
What type of cell is affected by sickle cell anemia? what is the effect?
Red blood cells. The shape of the cells are skewed, causing inadequate movement of the cells while transferring oxygen.
How is a "DNA fingerprint" produced?
Segments of DNA are "chopped up" and spread out on a gel.
What does gel electrophoresis accomplish?
Separates DNA fragments by length
Approximately how many restriction enzymes have been discovered?
Several thousand
What fragments move faster through a gel?
Shorter
what does PCR (polymerase chain reaction) accomplish
Solves the problem of small DNA sample Size.
What is the name given to the types of ends produced by BamHI?
Sticky ends
What were drawbacks in this method of obtaining HGH?
Supply low High cost Safety issues
What are advantages of using biotechnology to produce HGH?
Supply up Cost down
Old DNA strand: ACTCAGTAGTCCGTA
TGAGTCATCAGGCAT
In general, how is the frequency of Down Syndrome related to the age of the mother? Compare the frequency for 20 year old and 40 year old mothers.
Age of Mother: Risk: 20 1/2000 40 1/100 (20x increase)
How are DNA fingerprints used in paternity testing?
All DNA bands in the child's lane must be accounted for, meaning both bands must match a mother and a father's band
In males, how many (of the four) "daughter cells" become sperm cells?
All four
What are the two "business ends" of a tRNA molecule?
Amino acid attachment site and mRNA attachment site
Where are restriction enzymes found in nature?
bacteria
Where do plasmids naturally occur?
bacteria cells
What does HGH stand for?
human growth hormone