Genetics Test Review Flashcards
What is a Nucleotide?
is the combination of a base, a sugar, and a phosphate.
What are the four different nitrogen bases in DNA?
A- adenine
T- thymine
C- cytosine
G- guanine
Each person contains a different combination of A-T and C-G pairs
3 phases of the cell cycle
- Interphase
- Mitosis (cell division)
- Cytokinesis
Mitosis purpose and end result
Purpose- for growth and to replace warn out cells.
End Result- to produces two identical daughter cells.
Phases and structures involved for Mitosis
Interphase:
-Nuclear Membrane
-Chromatin
-Centrioles
-Neucleus
Prophase:
-Spindle Fibres form from your centrioles
-Chromosomes become dense
-Neuclear Membrane dissolves
Metaphase:
-Sister Chromatids meet in the middle on the equator
-Centrioles
Anaphase:
-Sister Chromatids are pulled to opposite sides of the cell
-Centrioles
Telophase:
-Cytoplasm stars to split
-Nuclear membrane forms
Meiosis I and Meiosis II
(Photo)
Difference between Mitosis and Meiosis
Mitosis:
-For growth and repair
-Produced 2 identical daughter cells and incurs in the somatic (body) cells
-Diploid (2n)
Meiosis:
-For sexual reproduction
-Produces 4 unique gametes and occurs in the sex cells
-Haploid (n)
Terms:
Sister Chromatid
A chromosome and its duplicate, attached to one another by a centromere.
Chromatid
A single stranded chromosome.
Centromere
Structure that holds together chromatids.
Homologous Pair
Paired chromosomes, similar in size, shape, gene arrangement, and gene formation.
Allele
Different forms of the same gene.
(E.x. Different hair colour).
Crossing Over
The exchange of genetic material between homologous chromosomes.
Gametes
Sex Cells (sperm and egg cells), have diploid number of chromosomes.
Haploid? What is it referred to? How many do humans have?
Refers to the number of chromosomes in a gamete.
Referred to as N.
In humans the haploid number of chromosomes is 23.
Diploid. What is it referred to? How many do humans have?
Refers to twice the number of chromosomes in a gamete.
Referred to as 2N.
In humans the diploid number of chromosomes is 46.
every cell in the body is diploid except sex cells
Synapsis
Pairing of homologous chromosomes.
Mistakes in meiosis:
Deletion
A piece of chromosome is deleted.
Mistakes in meiosis:
Inversion
A section is inverted.
Mistakes in meiosis:
Duplication
A section of chromosome appears 2 or more times in a row.
Mistakes in meiosis:
Translocation
A segment of one chromosome becomes attached to a different chromosome.
Non-disjunction
When homologous chromosomes or sister chromatids do not separate as they should during anaphase I or II of meiosis.
Monosomy
One chromosome is lost due to non disjunction.
Trisomy
The gain of an extra chromosome due to non-disjunction.
most common in chromosome 21, 18, and 13
Autosomes
22 pairs of chromosomes (non sex chromosomes).
remaining 1 pair is the sex chromosome (determines sex of individual
Genders:
Female? Male?
Female: XX
Male: XY
Mistakes in meiosis results:
Turner Syndrome Characteristics
Short stature
Webbed neck
Sexually underdeveloped
Mistakes in meiosis results:
Klienefelter Syndrome Characteristics
Sexually immaturity (inability to produce sperm)
Breast swelling
Mistakes in meiosis results:
Down Syndrome Characteristics
Almond shaped eyes
Flattened face
Short stature
Reproductive Technologies
Invitro & PGD
For humans — Invitro & PGD
- The technique used to fertilize egg cells outside the females body
- Offers a reproductive solution for women who have blocked fallopian tubes
- May require multiple attempts and may also be emotionally challenging for couple
- Many wonder if people will find ways to abuse the technology and if there’s a limit to how far we should go with them
Reproductive Technologies
Gene Cloning
Gene Cloning:
- The use of DNA manipulation techniques to produce multiple copies of a single gene or segment of DNA.
- Proteins produced in this way have numerous commercial and medical applications.
- Before gene cloning, people with diabetes used purified insulin from animal sources.
- Insulin was expensive to produce.
- Many people have concerns about the potential misuse of cloning technology.
Law of Segregation
Traits are determined by 2 alleles of a gene.
Law of Independent Assortment
The alleles from different traits segregate independently from one another, meaning that the inheritance of one trait does not affect the inheritance of another trait.
this is why we are so unique, because our gene assortment is so specific
Genotype
The genetic combination of gametes for a trait.
E.x. The collection of alleles that an individual contains.
Phenotype
The physical appearance of a trait, based in genotype.
E.x. RR = Physically round pea.
Dominant
The form of a trait that is always expressed when an individual has an allele for it.
E.x. Rr or RR = Round pea.
Recessive
The form of a trait that will only be expressed if the individual has 2 alleles for it.
E.x. rr = wrinkled pea.
Homologous
Describes the genotype of an individual with 2 alleles that are the same.
E.x. RR = homologous dominant
rr = homologous recessive
Heterozygous
Described the genotype of an individual with 2 alleles that are different.
E.x. Rr, the phenotypic expression (observed trait) is always the dominant allele.
Complete Dominance
When one allele in a pair completely masks the effect of the other allele.
So if a dominant allele is present it will always be expressed in the phenotype.
Monohybrid Crosses:
What will the F1 generation be ur a mother who is heterozygous dominant for brown eyes mates with a father with blue eyes.
UPLOAD PHOTO.
Dihybrid Crosses:
Determine the genotype and phenotypic ratios got the F1 generation for the following mating:
A homozygous free earlobes, heterozygous widows peak mates with attached earlobe, straight hairline.
UPLOAD PHOTO
Patterns of inheritance and disorders:
Autosomal Inheritance
Inheriting traits from genes on the autosomal chromosomes.
autosomal genes can be responsible for many inherited genetic disorders
Patterns of inheritance and disorders:
Autosomal Dominant Disorder, give an example.
Occurs when disease causing allele is dominant and the individual had one or both copies of the allele.
affected parents can have an unaffected child
E.x. Huntingtons disease.
Patterns of inheritance and disorders:
Autosomal Recessive Disorders, give an example.
Inheritance of a recessive phenotype located on gene of an autosomal chromosome.
2 unaffected parents can have an affected child (only happens if both parents are carriers)
E.x. Cystic Fibrosis
Incomplete Dominance (e.x. Red & White)
No allele is either dominant or recessive.
2 different alleles combine in the zygote.
The pink colour is produced by the blending of red and white alleles.
UPLOAD PHOTO
Co-Dominance (e.x. Red and White)
(E.x. Miss.Kwan’s thumbs)
Where both alleles are expressed at the same time.
UPLOAD PHOTO
Difference between Incomplete Dominance and Co-Dominance? (e.x. colour pink)
C= Incomplete Dominance
R W
E.x. C C
H= Co-Dominance
R W
E.x. H H
Multiple Alleles:
Human blood type contain how many alleles? What are they?
Human blood constitute a series of 3 multiple alleles.
A
I = a dominant alleles- produces antigen A on the red blood cells.
B A
I = co dominant with I - produces antigen B on the red blood cells.
O
I = recessive allele- produced O antigen on the red blood cells.
UPLOAD PHOTO
Antibodies:
What are the blood types? Genotypes? Antigen present? And antibody present?
Everyone has antibodies that react with foreign antigens to cause clumping or agglutination which can be fatal.
E.x. Antigen A would be agglutinated by antibody A.
UPLOAD PHOTO
Multiple Alleles:
What are the blood types? Who can each receive from and donate to?
UPLOAD PHOTO
X Linked Traits:
Carrier Hemophilia and Hemophiliac mate.
UPLOAD PHOTO
