Basic Genetics Flashcards
(87 cards)
1
Q
Describe Population Genetics?
A
The study of genetic traits withing a large population:
- Mendel’s law of inheritence
- Hardy-Weinberg Principle
- Inheritance patterns
2
Q
Cellular genetic pertains to?
A
The cellular organization of genetic material
3
Q
Molecular genetics pertains to?
A
The biochemistry of genes and the structures that support genes.
4
Q
Wohat are genes?
A
A section of DNA on a chromosome
5
Q
What are alleles?
A
One of two or more diffefrent allels that occupy a specific locus on a chromosome
6
Q
What does the locus refer to?
A
The specific location of a gene on a chromosome.
7
Q
What is a Amorph?
A
A silent gene; gene that does not produce a detectable antigen, such as Jk, Lu, O
8
Q
What is genotype?
A
Individuals genetic makeup (inherited genes)
9
Q
Phenotype?
A
Produced by the geneotype, it is the observable characteristics.
Ex: an enzyme to control blood group antigens; bone length (height)
10
Q
What is a Dominant gene?
A
Characteristic expresses even if carried on one of the homologous chromosomes.
11
Q
What is a recessive gene?
A
A gene that in the prescence of its dominant allele is not expressed.
12
Q
What is a co-dominant gene?
A
Both genes are expressed, they are not dominant over one another.
13
Q
What is Homozygous?
A
Same allele on both chromosomes
14
Q
What is Heterozygous?
A
Different alleles on both chromosomes
15
Q
Autosomal?
A
A trait not carried on the sex chromosomes
16
Q
What is autosomal dominant?
A
Traits physically expressed by all members of the family that carry of the allele.
***A pattern of inheritance in which an affected individual has one copy of a mutant gene and one normal gene on a pair of autosomal chromosomes.***
17
Q
What does Prokaryotic mean?
A
organism without a defined nucleus (bacteria and archea)
18
Q
What does Eukaryotic mean?
A
With a nucleus (all mammals)
19
Q
What are Histones?
A
Long polymers of DNA and various proteins that are compacted to form chromosomes during cell division.
20
Q
Who was Gregor Mendel?
What did Mendel refer to genes as?
A
An Austrian monk and mathmatician that observed pea plants to study how physical traits are inherited.
Elementen
21
Q
Who does Medel’s law apply to?
A
All sexully producing dipliod organisms
22
Q
What observable characteristics did Mendel study in pea plants? (3)
A
- Flower color
- Seed color
- Seed shape
23
Q
What did Mendel base his first law; the law of inheritance on, the law or independent or random segregation?
A
His results from his observations of the flower and seed color and seed shape from the pea plants
24
Q
What is Mendel’s First Law?
A
Law of independent segregation (random segregation)
Alleles have no permenent effect on one another when present in the same plant but segregate unchanged by passing into different gametes.
25
Mendel's 2nd Law:
If a homozygote dominant for two characteristics is crossed with a homozygote tha is recessive for both characteristics, what phenotype will the offspring have?
Offspring will have the same phenotype as the dominant parent.
26
What is Mendel's 2nd Law?
What in his studies did he base this law on?
The law of independent assortment
Different types of seeds produced by peas (green, yellow and textured; smooth / wrinkled)
27
What is the first generation of Mendel's study called?
What color were the flowers (trait)?
Parental pure (P1)
All red or all white (homozygous)
28
What is the First Filial generation and what trait was observed in their offspring?
* P1 generation was crossbred producing the second generation called **First Filial (F1)** that were all red.
* Dominant trait is the only trait observed. All plants are heterozygous (hybrid) for flower color (Rr)
29
What happened when the F1 generation were crossbred to eachother? What is the name of the generation was produced?
Why was this result produced?
* Red to white flowers produced in a 3:1 ratio
* Second-filial (F2)
* Because plants that have the R gene are either RR (homo) or Rr (hetero) have red flowers because red gene is Dominant.
* White flower is recessive and must occur in rr to be visible phenotype.
30
When is Partial Dominance observed?
What is important to remember regarding the above phenotype?
When the phenotype of a heterozygous organism is a mixture of both the homozygous phenotypes seen in P1
Although the phenotype does not show dominance or recessive traits, the F1 generation has the heterozygous type Rr.
31
How are most blood groups inhertited?
* Co-Dominant manner
32
What is Co-Dominance?
Both alleles are expressed, and their genes seen at the phenotypic level.
Example: a heterozygous MN individual will type as both M and N antigen positive.
33
What are Punnett squares?
Used to determine the possible ways alleles can combine to express a phenotype.
34
What are the Exceptions to Mendel's Laws?
* Genes for a seperate trait **_closely linked_** on a chromosome, can be **_inherited as a single unit_**
* Differences in gene ratios of progeny of F1 mating, if **_recombination_** has occured by **_meiosis_**.
35
What are some examples of **recombination**?
* Blood group systems MNSs; MN and Ss are allels physically close on the same chomosome and are therefore linked.
* DNA strands broken and there is an exchange of chromosomal material followed by activation of DNA repair mechanisms.
* Exchange of chromosomal materials results in a a new hybris that may or may not be seen at the phenotypic level.
36
G.H. Hardy, a mathematician, and W. Weinberg, a physician developed a mathematical formula that allows the study of?
* Mendelian inheritance in detail.
37
What is the criteria outlined in the Hardy-Weinberg Principle?
* Population studied must be large
* Mating among individals is random
* Mutations must not occur in parents or offspring
* NO migration, differential fertility, or mortality of genotypes studied.
38
What is Pedigree?
The trait to be studied
39
In pedigree analysis what represents males and females and a mating between a pair?
* Males = square
* Females = circles
* Line joining the two
40
How are offspring indicated in pedigree analysis?
* Indicated by a verticle line
41
What indicates a consanguineous mating?
A double line between a male and female
42
What indicates a still birth in pedigree analysis?
a small black circle
43
In pedigree analysis what represents a deceased family members?
A line through them.
44
What is the **propositus**?
The most interesting or important member of the pedigree(arrow points to them)
* The initial individual whose condition led to the investigation of hereditary disorder or to a serological evaluation of family members.
45
Inheritance patterns: What does autosomal refer to?
Traits not carried on the sex chromosomes
46
What is a recessive trait?
Is carried by either parent or both parents but is not generally seen at the phenotypic level unless both parents carry the trait
47
What is autosomal recessive?
Two heterozygous individuas mate, they can make a child with a a recessive gene from each parent and is therefore **homozygous** for that recessive trait.
Example both parents are Rh-type Dd and have a child who is dd which is Rh-negative
48
What is **autosomal dominance**?
* All family members carry the allele and show the physical characteristic.
* At least one parent has the gene and it is expressed if only one copy of the gene is present.
* Passed from one generation to the next and do not skip generations.
49
T/F: Unlike X-linked traits, autosomal traits do not normally show a difference in the distribution between males and females, a helpful clue in their evaluation.
True
50
X-linked dominant male has sons and daughters?
Why does the above happen?
* If a man has a trait on his x chromosome, he has no sons with that trait but all his daughters will have the trait.
* Because a male always passes on his Y chomosomes to sons and X chromosome to his daughters.
51
X-linked dominant female how are their sons and daughters affected?
* Women can be homozygous (xx) or heterozygous (Xx) for an x-linked trait. So when daughters inherit the trait in a way similar to autosomal inheritance so either dominant of unaffacted.
* * Because the trait is dominant, sons who in herit it will express it.
52
Explain x-linked recessived inheritance with affected males vs. affected females?
* The father always expresses the trait but never passes it on to his sons. But always passes the trait to his daughters, who will be carriers of the trait.
* The female carriers will pass on the trait to **half (50%)** of their sons who will also be carriers.
* In the homozygous state, XY males express the trait (only one X) whereas only the rare homozygous females, XX, will express the trait. (one normal x = carrier)
53
What blood group system follows an x-linked pattern?
Xga
54
What disease is an example of an X-linked recessive pattern?
Hemophilia A
55
What are the two major categories cells/organisms are divided in to?
Prokaryotes and Eukaryotes
56
What is an example of an Autosomal dominant gene in transfusion medicine?
Lu supressor gene
57
What is an example of an Autosomal recessive gene in transfusion medicine?
dd genotype
58
What is chromatin?
contained within the cell nucleus, made up of protein RNA and DNA, and structural proteins that are defined by staining patterns.
59
What are the three types of chromatin describe staining patterns?
* Heterochromatin - stains as dark bands
* Achromatin - stains as light bands, highly condensed regions not transcriptionally active.
* Euchromatin - the swollen form of chromatin, which is more acive in systhesis of RNA for transcription, usually stains light.
60
What are the only organisms that diplay partial dominance?
Plants
61
What are chromosomes?
* long linear stands of DNA coiled around highly basic proteins called histones.
* made from a single DNA molecule
* appear as rod-like bodies
* each molecule is a single DNA molecule
62
What specifies the genetic code?
DNA
63
Whae helps maintain chromosome shape?
Histones
64
What controls the activity of certain regions of DNA
Nonhistones
65
During which part of cell divsion does a single chromosome replicate and become two identical chromosomes connected at the center by a centromere?
Metaphase
66
A gene carries biological information that must be copies and transmitted to each cel from its \_\_\_\_\_\_\_
Progeny
67
What is an allele?
A gene that has more than one form, any of which may occuoy a single locus on a chromosome.
Different forms of a gene are alleles
68
What is Locus?
The location of a gene on a chromosome.
69
What is the Cis position?
Location of two or more genes on the same chromosome of a homologus pair
70
What is the Trans position?
Location of two or more genes on opposite chromosomes on a homologous pair.
\*\*C in the trans position suppress the expression of D gene\*\*
71
What is heredity?
the transmision of traits from parents to offspring
72
What is geneotype?
The sequence DNA that is inherited on the chromosome (individual genetic makeup). The alleles
73
T/F - Phenotype cannot be detected through serological testing.
True
74
How many distinct stages is the cell cycle divided in to?
Four
75
Describe each of the following stages of the cell cycle:
* Resting stage (G0)
* Pre-replication stage (G1)
* S Stage
* Post-replication stage (G2)
* M phase
* State of cell NOT dividing
* RNA produces and protein sythesized
* DNA Synthesis
* GAP between DNA synth and mitosis - cell cont. to synth RNA and proteins
* Mitosis occurs
76
What is Mitosis?
The process of cells divion to create identical daughter cells.
chromosomes duplicated and one of each pair is passed to each daughter cell.
DNA delivered to daughter cells by cell division
77
What characterizes the stages of mitosis?
Appearance and movement of chromosomes
78
What are the stages of mitosis?
* **I**nterphase
* **P**rophase
* **M**etaphase
* **A**naphase
* **T**elophase
79
What is interphase?
* DNA in chromatin form and dispersed
* cells not dispersed
* syth. RNA and Proteins
80
What is Prophase?
* Chromatin condenses
* nuclear envelope breakdown
81
What is Metaphase?
Chromosomes lined up in middle of cell and paired with corresponding chromosome.
This is the stage chromosome preperations are done for cytogentic analysis.
82
What is Anaphase?
* Spindle aparatus formed
* chromosomes pulled to opposite ends of the cell.
* cell becomes pinched in the middle
* Start of cell division
83
What is Telophase?
* Cell is pulled apart
* division complete
* chromosomes and cytoplasm pulled into to new daughter cells
84
What is Meiosis?
Different process of division to produce gametes or sex cells
Gametes are **Hapliod**
85
What are the Stages of Meiosis?
* **I**nterphase I (2N)
* **P**rophase I (4N)
* **M**etaphase I (4N)
* **A**naphase I (4N)
* **T**elophase (2N)
* **M**etapahase II (2N)
* **A**naphase II (N)
* **T**elophase II (N)
86
Describe the stages of Mieosis?
Interphase I (2N) - Resting stage, RNA and protein synthesis.
Prophase I (4N) - First stage of meiosis, chromatin condenses, chromosomes pair and become **Bivalent. Chromosome crossing over)**
Metaphase I (4N) - Allign in centre. Bivalent chromosome containt all 4 cells copies of each chromosome.
Anaphase I (4N) - Homologue pairs move to opposite ends of cell.
Telophase (2N) - cells seperate to form 2 daughter cells that are 2N
Metapahase II (2N) - Homologues line up at equator.
Anaphase II (N) - move to opposite poles
Telophase II (N) - Each cell sperates into two new cells with now four (N) cells
87
The uniqueness of daughter cells generated in meiosis allows for?
Genetic Diversity and controls the # of chromosomes within dividing cells.
