Genetic diseases Flashcards
(43 cards)
1
Q
Genetics
A
- Study of heredity in general and of genes in particular
2
Q
Heredity
A
- The passing of the traits from the parent to offspring (inheritance)
3
Q
Phenotype
A
- The indavidulas observable traits
4
Q
Genotype
A
- The set of genes in our DNA which are responsible for a particular trait
5
Q
True breeding
A
When the plants self-pollinate, all their offspring are of the same variety
6
Q
Hybridisation
A
Mating, or crossing, of two varieties
7
Q
Monohybrid cross
A
A cross between two parents that breed true for different versions of a single trait
8
Q
Homozygous
A
An organism possessing two identical alleles for that trait (gene)
9
Q
Heterozygous
A
An organism possessing two different alleles for that trait (gene)
10
Q
Somatic mutations
A
Changes to the DNA of somatic cells after the birth, its non-heritable
11
Q
From DNA to protiens
A
- DNA sequence transcribed into RNA
- Mature mRNA is translated into proteins. RNA sequence is read consecutively in groups of three consecutive nucleotides (codons), from the start codons
- Codons are nonoverlapping and the message has no gaps
- There are stop codons that block the translation
12
Q
Single gene disorder
A
- Mutations can lead to a gain-of-function but also to a loss-of-function
- The resulting protein alteration/deficiency is responsible for the disease symptoms
- A condition that is present from birth
13
Q
Autosomal dominant
A
If a single mutated allele is sufficient to cause the disease (heterozygosis)
14
Q
Autosomal recessive
A
If both mutated allele must be inherited to be affected (homozygosis)
15
Q
X-linked recessive or dominant
A
Mutated gene is present on the X chromosome
16
Q
Missense mutations
A
- These are base changes that alter the codon for an amino acid resulting in its replacement with a different amino acid
17
Q
Nonsense mutations
A
- Base changes that convert an amino acid codon to a stop codon, resulting in a premature termination of translation and the production of a shortened protein
18
Q
Silent mutations
A
Do not cause any change in an amino acid
19
Q
Frameshift mutation
A
- These mutations result from the insertion or deletion of one or more bases causing the alteration of the reading frame of the gene and a different set of codons, leading to an altered protein
20
Q
Promoter mutations
A
- Affect the way gene transcription is regulated, often abnormally reducing or enhancing the expression of certain genes
21
Q
Sickle Cell Anaemia
A
- Autosomal recessive
- Caused by homozygous gene mutation beta globlin gene
- Red blood cells form an abnormal crescent shape
- Haemoglobin (protein) is abnormally shaped
- Don’t move easily through your blood vessels
- Form clumps and get stuck in the blood vessels
22
Q
Numerical Abnormalities
A
- When an individual is missing either a chromosome from a pair or has more than two chromosomes of a pair
23
Q
Structural Abnormalities
A
When the chromosome’s structure is altered
24
Q
Euploid
A
- 46 chromosomes in somatic cells which is 22 chromasomes and 2 sex chromasomes
25
Aneuploid
- Results from nondisjunction in meiosis of the germ line cells leading to genetically unbalanced eggs or sperm
Monosomy - only one of a particular type of chromosome
Trisomy - three of a particular type of chromosome
26
Nondisjunction
- Abnormal mumber of chromasomes chromasomes in each cell
- Can cause some some forms
27
Stomatic mosaicism
- Two or more cell lines with different chromosome compositions in an individual
28
Trisomy
- Occurs when an individual has three of a particular type of chromosome
29
Downs syndrome
- Short stature
- Eyelid fold
- Flat face
- Stubby fingers
- Wide gap between first and second toes
30
Edward Syndrome
- A small, abnormally shaped head
a small jaw and mouth
delayed growth
- Trisomy extra chromasome
31
Patau syndrome
- Mental deficiency
- Severe central nervous malformations
- Sloping forehead, malformed head
- Scalp defect
- Trisomy extra chromasome 13
32
Turner syndrome
- Female born with single X chromasome
- Short, with broad chest and widely spaced nipples
- Can be of normal intelligence and function with hormone therapy
- Life expectancy is normal in most cases
33
Klinefelter syndrome
- Male with underdeveloped testes and prostate; some breast overdevelopment
- Long arms and legs; large hands
- Near normal intelligence
- No matter how many X chromosomes, presence of Y renders individual male
- XXY chromasome Trisomy
34
Deleation mutation
- One or both ends of chromasome breaks off
- 2 breaks at the same time causes loss of internal segment
35
Duplication mutation
- Chromasomal segment more than once in the same chromasome
36
Inversion mutation
- Chromasome is broken down and inverted and reattached
- Gene occours in reversed order
37
Translocation mutation
- Portion of chromasome is transfered to another chromasome
- Insertion which causes a frame shift
- Robertsonian follows breakage of two nonhomologous chromosomes and improper re-assembly
38
Multifactor disorder
- Familiar clustering but doesn't conform to single gene inheretance
- Non communicable no change in DNA but there is a change in expression with the effects of environment
- Additive effects impacts on gene
- Type 2 diabetes caused by genes and environment
39
Cancer
- Genetic (breast cancer) but not necessarily inherited dependant on environment and gene
- Only germ line inherited other cancers are somatic
- Unregulated cell proliferation - undetect mistakes in the DNA caould cause DNA replication faster
40
Malignant tumor
- Uncontrolled cell division that has a metastatic spread
- Spread of the cells by breaking away
- Via lyphatic or blood
- loose cellular funtion and apoptosis
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Mutation of Oncogenes
- Activation stimulates cell growth and division in response to specific signals
- In cancers its predominently switched on
42
Mutations of tumor supressor gene
- Unable to block or regulate division
- Cell is unable to undergo apoptosis
- Permenently switched off (P53)
43
Genetic polymorphism
- 2 or more diffrent forms of Dna sequence on the same locus present in 1% of a population
- Due to susbstitution of single nucleotide (SNPs)
- Determine the diversity of indaviduals and sometimes have a role in drig response present risk factors for disease
