1
Q
Characters or Traits
A
Individual biological properties of a species
2
Q
Wild type
A
The most common form of any trait of an organism that is found “in the wild,” or in nature.
3
Q
Mutants + they arise by (2)
A
The heritable variants observed in a species that differ from wild type. Arise by from wild types by a process called mutation
4
Q
Mutation results in____ and is also known as
A
heritable changes in the DNA of a gene
The changed form of the gene
5
Q
Mutations arise by
A
mistakes in cellular processing of DNA
6
Q
Genetic dissection/Gene discovery (3)
A
- Gene discovery starts with a “hunt” to amass mutants for the biological function under investigation. One widely used method is to treat the organism with radiation or chemicals that increase the mutation rate.
- The test for single-gene inheritance is to mate individuals showing the mutant phenotype with wild-type individuals, and then to analyze the first and second generations of descendants. In each generation, the diagnostic ratios of plants with blue flowers to those with white flowers will reveal whether a single gene controls white versus blue flower color.
- Other mutations affecting flower color (per- haps mauve, blotched, striped, and so on) would be ana- lyzed in the same way, resulting overall in a set of defined “flower-color genes.” Through genetics, the set of gene functions that interact to produce the trait we call flower color can be defined.
7
Q
Forward genetics
A
A strategy to understanding biological function starting with random single-gene mutants and ending with their DNA sequence and biochemical function
8
Q
Reverse genetics
A
Reverse genetics starts with genomic analysis at the DNA level to identify a set of genes as candidates for encoding the biological trait of interest, then induces mutants targeted specifically to those genes, and then examines the mutant phenotypes to see if they indeed affect the trait under study.)
9
Q
What do genes do?
A
encode proteins or RNA molecules that facilitate or regulate protein expression
10
Q
Pure lines
A
organisms with homogenous genetic constituents
11
Q
self pollination
A
allowing pollen from a flower to fall on its own stigma
12
Q
The slash shows that
Y/Y, y/y, or Y/y
A
the alleles are a pair
13
Q
Mendel’s first law or the law of equal segregation
A
In meiosis, the members of a gene pair separate equally into the cells that become eggs and sperm, the gametes. Hence, a single gamete contains only one member of the gene pair.
14
Q
zygote
A
the first cell that develops into a progeny individual
15
Q
homozygote
A
a pair of identical alleles for a given gene
16
Q
heterozygote
A
the alleles of the gene pair differ
17
Q
monohybrid
A
a heterozygote for one gene
18
Q
monohybrid cross
A
a cross of the type Y /y ×Y /y
19
Q
Somatic cell division +product (2)
A
Division of cells of the main body, known as the soma. The products of somatic cell division are exact copies of the parent cell.
20
Q
Sexual cell division (4)
Where it takes place+ what divides+ what produced in pant/fungi+alge
A
- Takes place in sex organs.
- Specialized cells called meiocytes divide to produce sex cells such as sperm and eggs in plants and animals, or sexual spores in fungi or algae
21
Q
n =
A
the number of chromosomes in the genome
22
Q
diploid (2)
A
- 2n somatic cells
- the chromosomes are in pairs
23
Q
homologous chromosomes
A
the two members of a pair (Diploid)
24
Q
haploid
A
just one chromosome set, n
25
Mitosis illustrated with n and 2n
either 2n → 2n + 2n
or n → n + n
26
Meiosis takes place only in________, and the resulting gametes are _______
diploid cells, and the result- ing gametes are haploid
27
meiosus illustrated with 2n
2n → n + n + n + n
28
Mitosis in diploid (3)
- At the onset of mitosis in somatic cells, the chromosomes condense by coiling to become shorter, and they are seen to have duplicated to form daughter units called chromatids
- Each pair of chromatids aligns on the equatorial plane of the cell and then, as the cell divides, molecular threads called spindle fibers attach to the centromere and pull one sister chromatid into each daughter cell as the centromere divides.
- Once in the daughter cells, the chromatids become individual chro- mosomes in their own right.
29
S phase
DNA replication
30
Meiosis difference than mitosis:
The two homologous chromosomes pair to form a group of four chromatids at the equatorial plane. In the first division, the centromere holding a pair of sister chromatids together does not divide. One pair of chromatids is pulled into each daughter cell by spindles that attach to the undivided centromeres. At the second division of meiosis, the centromeres divide; and now each chromatid is pulled into its own cell, which is now effectively haploid
31
Mitosis in haploid
Mitosis in haploids progresses in much the same way, but in haploid organisms, each somatic cell bears only one chromosome set
32
Meiosis in Haploids
In haploids, meiosis takes place at one special stage of the life cycle when two haploid cells unite to form a tran- sient diploid meiocyte. This cell union is a type of sexual union, although haploids generally do not have true sexes.
33
What are the structural differences between wild-type and mutant alleles at the DNA level of a gene?
They are generally found to be identical in most of their sequences and differ only at one or several nucleotides of the hundreds or thousands of nucleotides that make up the gene.
34
If the nucleotide sequence of an allele changes as the result of a rare chemical “accident,” a new mutant allele is created. Such changes can occur ____ and can be a change in -------,----,------
Such changes can occur anywhere along the nucleotide sequence of a gene. For example, a mutation could be a change in the identity of a single nucleotide, or the deletion of one or more nucleotides, or even the addition of one or more nucleotides.
35
The mutational damage can occur
at any one of many different sites
36
When is DNA replicated?
During S phase
37
The replication of DNA during the S phase produces
two copies of each of the alleles A and a
38
At the molecular level, the primary phenotype of a gene is
the protein it produces
39
exons
The protein-coding regions of a gene
40
introns
noncoding regions of the gene
41
Most mutations that alter phenotype alter ....
the amino acid sequence of the gene’s protein product, resulting in reduced or absent function.
42
null allele
the proteins encoded by them completely lack the gene's WT/normal function
43
leaky mutations
Mutant alleles that reduce the level of enzyme function, partial inactivation of the wildtype function. Some wild-type function seems to “leak” into the mutant phenotype.
44
haplosufficient+heterozygotes (2)
- Although a wild-type diploid cell normally has two fully functional copies of a gene, one copy of a haplosufficient gene provides enough gene product (generally a protein) to carry out the normal transactions of the cell.
- In a heterozygote (say, +/m, where m is a null allele), the single functional copy encoded by the + allele provides enough protein product for normal cellular function.
45
Recessiveness is observed in null mutations in genes that are functionally
haplosufficient
46
haploinsufficient+ dominat?
| What would be dominant?
In such cases, a null mutant allele will be dominant because, in a heterozygote (+/P), the single wild-type allele cannot provide enough product for normal function and the mutated allele is dominant
47
As a general rule, a null mutation is ----- in a haplosufficient gene, and a null mutation is --- in a haploinsufficient gene.
recessive
dominant
48
A cross between heterozygous domi- nant and wild type parents will result in a --- phenotypic ratio in the progeny.
1:1
49
The principles of inheritance (such as the law of equal segregation) can be applied in two directions:
1. inferring genotypes from phenotypic ratios
2. predicting phenotypic ratios from parents of known genotypes.
50
Human body cells have 46 chromosomes:
22 homologous pairs of autosomes plus 2 sex chromosomes
51
homogametic sex
the gametes are of only one type (ex: XX)
52
heterogametic sex
the sex chromosomes differ (ex: XY)
53
Dioecious species+ex
those showing animal-like sexual dimorphism, with female plants bearing flowers containing only ovaries and male plants bearing flowers containing only anthers
54
hemizygous+ex
The differential region of the X chromosome contains many hundreds of genes; most of these genes do not take part in sexual function, and they influence a great range of human properties. The Y chromosome contains only a few dozen genes. Some of these genes have counterparts on the X chromosome, but most do not. The latter type take part in male sexual function.
55
Differential region
The differential regions, which contain most of the genes, have no counterparts on the other sex chromosome.
56
pseudoautosomal regions 1 and 2
The human X and Y chromosomes have two short homologous regions, one at each end. In the sense that these regions are homologous, they are autosomal like and they pair up here
57
What places in the chromosome cross over in sex chromosomes?
pseudoautosomal regions 1 and 2
58
The affected phenotype of an autosomal recessive disorder is inherited as a recessive allele; hence, the corresponding unaffected phenotype must be
inherited as the correspond- ing dominant allele
59
the term wild type and its allele symbols are not used in ..... because.....
the term wild type and its allele symbols are not used in human genetics because wild type is impossible to define
60
In human pedigrees, an autosomal recessive disorder is generally revealed by
the appearance of the disorder in the male and female progeny of unaffected parents.
61
P arm
shorter arm
62
metacentric
chromosome arm the same length
63
# Arocentric
Arocentric
64
A full set of sister chromatids is created during the
S phase
65
Sister chromatids have the--------, non sister chromatids can be same if ------ or different if-----
Sister chromatids have the exact same alleles, non sister chromatids can be same if homozygote or different if heterozygote
66
In autosomal dominat pedigree.....
there is no skipping of generation
67
BIOL311
flashcards
Decks in class (15)
# Cards
-
Chapter 1: The Genetic Revolution35
-
Chapter 2: SINGLE-GENE INHERITANCE67
-
Chapter 3: Idependent Assortment16
-
Chapter 4: Mapping Eukaryotes19
-
Chapter 6: Bacteria and Viruses52
-
Topic 7: DNA structure and replication31
-
Topic 7: PCR15
-
Topic 7: Gel Electrophoresis9
-
Topic 8: DNA variation27
-
Topic 9: Transcription+Translation37
-
Topic 10: Prokaryotic Gene Regulation- Lac Operon53
-
Topic 11: Eukaryotic Gene regulation61
-
Topic 12: Cloning and Restriction Mapping21
-
Topic 13: Genetics of Development25
-
Topic 14: Crisper7
