ch 11 & 12 (genetics & protein synthesis) Flashcards
(93 cards)
1
Q
why did Gregor Mendel pick pea plants for his study?
A
because they…
grew quickly, were easy to cross-pollinate (breed), had distinct variations of characteristics
2
Q
what did Gregor Mendel do during his experiment/study? (steps)
A
- he started with a homozygous group, and let them self-pollinate for 2 years.
- HE then crossed them (tall and short) to make the F1 generation.
- he then crossed the F1 generation to make the F2 generation
3
Q
what did Mendel find in the F1 generation?
A
all of the individuals showed one characteristic (tall)
4
Q
what did Mendel find in the F2 generation?
A
75% were tall and 25% were short
5
Q
what did Mendel observe and then conclude?
A
observed- that the factor for short was still present in the F1 generation. It had to be hidden by the factor for tall
concluded- that some factors for a particular trait are dominant while others are recessive
6
Q
law of dominance
A
some factors for a particular trait are dominant while others are recessive
7
Q
law of segregation
A
states that alleles are separated from each other during the formation of gametes. The homologous chromosomes separate during meiosis.
8
Q
homozygous
A
same alleles (TT or tt)
9
Q
heterozygous
A
different alleles (Tt)
10
Q
Phenotype
A
physical characteristics/what it looks like (blue eyes)
11
Q
genotype
A
what alleles you have what gene combination
12
Q
what was Gregor Mendel
A
Scientist who grew plants and studied the passing of traits to offspring. discovered-
dominant and Recessive factors/ principle of dominance, Principle of segregation, Principle of Independent Assortment
13
Q
law of independent assortment
A
stated that when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.
14
Q
hybrid
A
the offspring of crosses between parents with different traits
15
Q
genes
A
chemical factors that determine traits
16
Q
incomplete Dominance
A
cases in which one allele is not completely dominant over another
17
Q
codominance
A
both alleles contribute to the phenotype
18
Q
multiple alleles
A
when many genes have more than two alleles
19
Q
Polygenic traits
A
traits controlled by two or more genes
20
Q
allele
A
the different forms of a gene
21
Q
why did Thomas Hunt Morgan pick fruit flies for his study
A
they were…
small in size, easy to keep in lab, able to produce large numbers of offspring in a short time
22
Q
Thomas Hunt Morgan
A
A scientist who applied Mendels Principles to the offspring of fruit flies
23
Q
what did MORGAN do and find during his study on fruit flies?
A
- Found that certain genes seemed to be inherited with each other.
- He grouped those genes that seemed to be linked together and found that THERE were 4 different groups
- found that it is not genes that assort independently , it is chromosomes. Those genes on the same chromosome move together during meiosis
24
Q
genes on the same chromosome move together during meiosis. what happens during meiosis that could change that ?
A
crossing over
25
who was Fedrick Griffin
a scientist who performed the first major experiment that led to the discovery of DNA as the genetic material. He performed the first demonstration of bacterial transformation
26
what were the 2 different types of bacterium Fredrick Griffin found?
smooth coat strain and rough strain
27
smooth coat strain (s)
bacterium which is lethal (cause death) to mice; disease-causing strain
28
rough strain (r)
bacterium which will not hurt the mouse
29
gene map
shows the relative locations of each known gene on a particular chromosome
30
what did Fedrick Griffin's do in his experiment?
he injected several different strains of the bacterium streptococcus pneumoniae into mice.
a. injected s strain into mouse. the mouse died
b. Injected r strain into mouse. the mouse lives
c. He heat-killed the S strain and then injected it into the mouse. the mouse lived.
d. He took a mixture with the heat-killed S strain, mixed with the r strain, and injected it into the mice. the mouse died
31
what Fedrick Griffin conclude from his experiment?
some material in the heat-killed S strain was responsible for "transforming" the R strain into a lethal form.
32
genetics
the scientific study of heredity
33
what interaction determines characteristics
the interaction between genes and the environment
34
what did Thomas Hunt Morgan conclude
Mendels principle still holds true and each chromosome is actually a group of linked genes
35
transformation
the process in which one strain of bacteria changes permanently into another
36
what did Owswald Avery, C.M. MacLeod, and M. McCarty conclude during their experiment?
that the genetic material responsible for the transformation was DNA. And that when S cells were killed, DNA was transferred
37
what did Oswald Avery and his team do during his experiment?
he continued Fedrick Griffin's work:
1. THey made 2 extracts from heat-killed bacteria and treated each one with different enzymes. one enzyme could break down DNA and the other proteins,lipids, carbohydrates, more molecules including RNA.
2. Thay then observed in which plate TRAnsformation did and did not occur
38
what was the debate between the genetic material responsible for the transformation?
DNA or Proteins
39
what were the results Oswald Avery's experiment?
transformation did not occur in the plate with DNA destroying enzymes when DNA was destroyed
transformation did occur in the plate with protein-destroying enzymes
40
who was Oswald Avery
a scientist who identified the molecule that transformed the R strain of bacteria into the S.
41
why did the R strain turn into S during Fedrick Griffin's experiment?
because when the S cells were killed, DNA was transferred and the R bacteria incorperated this DNA into their cells and turned into S cells
42
what is bacteriophage
a kind of virus that infects bacteria
43
What is fertilization?
process in sexual reproduction in which male and female reproductive cells join to form a new cell
44
true-breeding
organisms that produce offspring identical to themselves if allowed to self-pollinate
45
who was Hershey and Chase
scientists who used radioactive labeling to trace the DNA and PRotein
46
what makes up a bacteriophage
a protein coat and a DNA core
47
what did Hershey and Chase conclude?
that the genetic meterial in the bacteriophage was DNA NOT protein
48
what did Hershey and Chase do in their experiment
1. they grew viruses in clusters containing radioactive isotopes of phosphorus 32 (32P) and sulfur 35 (35S). (these substances could be used as markers)
2. IF 35 S was found in the bacteria it would mean that the virus is protein had been injected into the bacteria.
IF 32P was found in the bacteria then it was the DNA that had been injected
49
Gene linkage
the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction.
50
what did GREgor MEndel use pea plants to study for?
to study how characteristics go from one generation to the next.
51
explain the meaning of D and R in terms of alleles
D: an allele that produces the same phenotype whether its paired allele is identical or different
R: an allele that produces its characteristic phenotype only when its paired allele is identical.
52
what is the difference between a diploid and haploid
the # of chromosomes:
diploid: fullest set of chromosomes, contains two sets of homologous chromosomes
haploid: half a set of chromosomes
53
what are the 3 main types of RNA?
messenger RNA, transfer RNA, ribosomal RNA
54
what does messenger RNA do?
carriers copies of the instructions for assembling amino acids from DNA to the rest of the cell
55
what does transfer RNA do?
transfers each amino acid to the ribosome to help assemble proteins
56
what does ribosomal RNA do?
makes up the major part of ribose
57
list the 3 critical things that genes were known to do
1. genes had to carry info from one generation to the next
2. had to determine the haritable characteristics of organisms
3. had to be easily copied
58
what did x-ray diffraction help solve about dna
its structure, that it was a double helix
59
DNA is often is compared to a twisted later, what are the rails on the later represented by?
the alternating Deoxyribose and phosphate
60
on the top rail of DNA, what is the strand said to be oriented
5' to 3'
61
what is the strand on the bottom f DNA said to be oriented
3' to 5' (runs oposite to the top)
62
what forms the backbone of a DNA chain
it is formed by the sugar and phosphate groups of each nucleotide
63
what is the difference between codominance and incomplete dominace?
In codominance, both alleles are expressed at the same time without any blending and in incomplete dominance the two traits are blended
64
Where does RNA polymerase bind?
To the promoter
65
nucleotide
a Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
66
what do nucleosomes coil to form?
chromatin fibers
67
histones
proteins around which DNA is tightly coild to form nucleosomes
68
who was James Watson and Francis Crick
two scientists who developed the double-helix model of the structure of DNA
69
who was Erwin Chargraff
a scientist who discovered the percentages of guanine and cytosine bases are almost equal in any sample of DNA
70
Chargraff's rules
the observation that the percentage of adenine=thymide and the percentage of guanine=cytosine in the DNA molecule
71
why do parental strands of DNA separate?
to serve as templates and produce DNA molecules that have one strand of parental DNA and one strand of new DNA
72
what do nucleosomes do?
they fold enormous lengths of DNA into the cell nucleus
73
DNA Helicase
an enzyme that is responsible for unwinding and unzipping the double helix
74
DNA polymerase
an enzyme that continues adding appropriate nucleotides to the chain by adding 3' end of the new DNA strand
75
what happens to the leading strand as DNA unwinds
it is elongated
76
what happens to the LEading strand
it is synthesized continuously
77
what happens to the lagging strand
it elongates away from the replication fork and is synthesized discontinuously into small segments called Okazaki fragments
78
how is DNA replicated
the DNA strands are separated by the Helicase enzyme and held apart by another enzyme called RNA primase. While held open the DNA polymerase, slides along one strand of DNA placing nucleotides to build a matching copy. THe second strand, called the lagging strand, is copied by DNA polymerase.
79
transcription
the process in which part of the nucleotide sequence of DNA is copied into a complementary sequence
80
translation
decoding of a messenger RNA message into a polypeptide chain
81
codon
three-nucleotide sequences on messenger RNA that codes for a single amino acid; the 3 base code in DNA or mRNA (that tRNA reads)
82
base pairing
the principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine
83
intron
sequence of DNA that is not involved in in coding for the protein
84
exon
expressed sequence on DNA-codes for a protein
85
mutation
a permanent change that occurs in a call's DNA is called a mutation
86
what are 4 types of mutations
point mutation
insertion
deletion
frameshift
87
what are 3 things that can cause mutation
1. can occur spontaneously
2. chemicals and radiation can damage DNA
3. high-energy forms of radiation, such as x rays and gamma rays
88
somatic mutations
mutations in body cells, mutations that are not passed on to the next generation
89
what happens when mutations occur in sex cells
they are passed on to the organism's offspring and will be present in every one
90
operon
a group of genes operating together
91
what are 4 operons
operator, promoter, regulatory gene, genes coding for protein
92
how are proteins made?
1. in the nucleus, transcription begins. DNA matches with corresponding RNA bases making mRNA.
2. mRNA then leaves the nucleus and attaches to a ribosome. TRAnslation then begins.
3. tRNAs then match up with the corresponding bases on the mRNA, dropping off the amino acid it carries. making a chain of different amino acids which is a protein
93
what are the functions of DNA and RNA polymerase?
DNA poly. : Synthesizes a DNA strand and used in DNA replication
RNA poly. : Used during transcription to synthesize the mRNA strand
