Flashcards in Genetics Deck (45)
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1
Heredity
The passing of traits from parent to offspring
2
Describe the law of dominance....
Some traits can mask other traits when both traits appear in the parents.
Ex: Red is dominant to white
3
Describe the law of segregation.....
During the formation of reproductive cells (sperm, egg) the paired factors (genes) separate from one another and then recombine.
4
Describe the law of independent assortment...
Each trait is inherited independent of one another
(Exception: blond hair, blue eyes)
5
Factor-
Gene-
Allele-
Describing a gene (mendels word)
Trait
A form of a trait
6
Describe incomplete dominance....
The two alleles are neither dominant or recessive. Both contribute to the phenotype of the offspring. (Blending)
Ex: Snap dragons
7
Describe co-dominance and multiple alleles....
Two alleles may contribute equally in the offspring and are both dominant. (No blending)
Example: speckled chicken produced from a black chicken and white chicken.
Or blood types (Type AB has both A and B)
8
Describe sex linked traits....
All organisms that reproduce sexually have a combination of X and Y chromosomes.
Male: XY Female: XX
9
Acquired trait
Inherited trait
Trait that has been learned
Ex: scars, attitude
Trait passed from parent to offspring (or from ancestor)
Ex: eye colour
10
Autosome
Non sex chromosome
11
Carrier
A female that carries a gene but does not express it in her phenotype.
Ex: Hemophilia (XRXr)
12
Chromosome
Threadlike structure carrying genetic information in the form of genes
13
Diploid
A cell that contains two sets of homologous chromosomes
14
Fertilization
During sexual reproduction, an egg and sperm combine to form a zygote
15
Gamete
Sex cell (sperm or egg)
16
Genotype
Symbolic representation of a characteristic
17
Haploid
A cell that contains only a single set of genes
18
Heterozygous
Having two different alleles for a particular gene
19
Homologous
Chromosomes in which one set comes from the male parent and one set from the female parent
20
Homozygous
Having two identical alleles for a particular gene
21
Karyotype
Micro graph showing the number and visual appearance of the chromosomes
22
Meiosis
Cell division that results in 4 daughter cells each with half the chromosomes as the parent.
Formation of gamers
23
Multiple alleles
3 or more alternative forms of a gene
24
Non disjunction
Failure of homologous chromosomes or sister chromatids to separate during cell division.
25
Phenotype
Physical characteristic of an organism
26
Pedigree
Diagram that shows the occurrence and appearance or phenotype of a genetic trait from one generation to the next within a biological family
27
Test cross
Genetic cross between homozygous recessive and a suspected heterozygous to determine the genotype of the later.
28
Tetrads
4 chromatids in groups of 2 formed in prophase 1
29
Synapsis
Fusion of chromosome pairs at the start of meiosis that enables crossing over to occur
30
Cystic fibrosis cause and symptoms
Autosomal recessive Inherited disease passes a defective gene that causes buildup of thick mucus that can damage organs. Clogs lungs and is associated with digestive problems.
31
Down syndrome causes and symptoms
Nondisjunction causes an extra chromosome 21 which leads to cognitive impairment, flattened facial appearance and upward slanted eyes.
32
Hemophilia causes and symptoms
Sex linked trait that can lead to lack of blood clotting proteins. This creates excessive bleeding.
33
Kleinfelter’s syndrome causes and symptoms
Due to non disjunction a big is born with an extra X chromosome resulting in small testicles, breasts and reduced muscle mass.
34
Marfan syndrome causes and symptoms
Autosomal dominant: Mutation of gene that makes fibrin (protein in connective tissue) inherited from one parent. Leads to disproportionate legs and arms, heart murmurs, tall and slender build
35
Turners syndrome
A female with only 1 X chromosome due to non disjunction. Girls affected are short, infertile and have heart defects.
36
Huntington’s
Autosomal dominant disorder causing progressive breakdown of nerve cells in the brain. Leads to uncontrollable movements, difficulty with speech, lack of awareness
37
Sickle cell disease
Autosomal recessive disease where abnormal (sickle shaped) hemoglobin are inherited. Causes fatigue, pooling if blood in spleen, low resistance to infection, and pain.
38
Autosomal recessive
Autosomal dominant
Two copies of abnormal gene must be present in order to develop le disease.
One copy of abnormal gene from one parent needed to get disease.
39
Two names of cells that become sperm and egg
Oogonial (overly)
Spermatogonial (testes)
Both diploid or 2n
40
Describe meiosis 1
Interphase- DNA duplicates 46 chromosomes (92) chromatids
Prophase- DNA condenses and homologous pairs match up for crossing over to transfer genetic information.
Metaphase- Chromosomes in pairs at equator of cell
Anaphase- Chromosomes pulled away
Telophase and cytokinesis- 2 new nuclei form 2 new cells
41
Describe meiosis 2
Prophase 2-Spindle form
Metaphase 2- Chromosomes lime up in single file line
Anaphase 2- Chromatids pulled away
Telophase 2 and cytokinesis- 4 haploid cells formed
42
What is the meaning of each....
P
F1
F2
P=parental generation
F1- First filial generation
F2- Second filial generation
43
Purebred
Hybrid
Organism that is the offspring of genetically similar parents that were both homozygous for a trait.
Organism that is the offspring of genetically dissimilar parents.
44
Dominant
Recessive
Expressed in phenotype
Only expressed in phenotype when paired with another recessive allele
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