Genetics Flashcards
Genetics
What is sperm formation
Diploid spermatognia divide by mitosis to produce primary spermocytes. Primary spermocytes divide by meiosis to produce four functional cells called spermatids. These spermatids then undergo differentiation to become sperm cells
What is egg formation
Oogonia divide by mitosis to produce primary oocytes. Primary oocytes divide by meiosis to form one egg and three polar bodies. Therefore only ONE functional egg is produced because division of cytoplasm is not equal.
What is 1 abromality that effects the chromosomes
- Duplication
- duplication causes the repetition of a segment
Ex
Normal- VW-XYZ
Duplication- VW-XXYZ
What is 2 abromality that effects the chromosomes
Deletion
- Deletion causes the removal of a segment
Ex
Normal - VW-XYZ
deletion - VW -YZ
What is 3 abromality that effects the chromosomes
Inversion
- Inversion reverses the proper order of the genetic information (XYZ)
- Ex
Normal- VW-XYZ
inversion - VW-ZYX
What is 4 abromality that effects the chromosomes
Translocation
- translocation moves a segment from one chromosome to a non homologous one
Ex
Normal - ABCD-VW-XYZ
Translocation- AB-XYZ-VW-CD
What is non disjunction
Non disjunction is the failure of chromosomes to separate or move apart during meiosis
What is non disjunction in meiosis 1 and how is it diffrent than meiosis 2
Non disjunction in meiosis 1 is the separation of homologous chromosomes and resulting in aneuploidy (too many or too few chromosomes) this resulting in two gametes with an extra chromosomes and two missing a chromosome. None of the gametes are correct
What is non disjunction in meiosis 2 and how is it different than meiosis 1
Non disjunction in meiosis 2 is the separation of the sister chromatids resulting in half the gametes being normal and a monosomy(missing a chromosome) and polysomy(extra chromosomes)
What is a karyotype
A karyotype is a picture of all 46 chromosomes that is used to collect information regarding characteristics. When the cells are dividing they thicken and scientists use a chemical that stops mitosis at metaphase. Cells are then fixed, stained and pictures are taken with a microscope so that chromosomes are visible to naked eye. They are then stored in homologous pairs based on their size, banding patter, and centromere location.
How do you determine the sex of a human through chromosomes?
Humans have 46 chromosomes
22 identical pairs (Autosomes)
1 sex paid (sex chromosomes)
A female posses:
1 pair of XX chromosomes
A male posses:
1 pair of XY chromosomes
Male sperm can carry Y or X and that is what determines the sex of baby
What is amniocenteses
Amniocentesis is a genetic screening method. It involves a needle that is used to pull cells (centrifuged cells) from the amniotic fluid while the baby is still in the womb and is karyotypes for any chromosomal diseases or abromalitys on a certain chromosome (trisomy 18) and the sex of the baby.
What is IVF
In vitro fertilization is when mature eggs are collected from the overease and sperm is used to fertilize that egg in a dish. Scientists will screen these fertilized eggs to find one without any abromalitys as this is a way for people with genetic problems or older people to have children. The egg (zygote) is the placed back into the uterus of the woman.
What is polyploidy and how does it help certain things
Polyploidy is a condition in which an individual has sets of chromosomes greater than the normal diploid number (3n 4n etc) polyploids with even numbers are fertile as pairs can be formed but odd numbers are sterile as pairs cannot be formed. They are usually larger plants, make larger fruit, more vigorous. Animals that are polyploidy include salamanders, frogs, leeches and some fish. There is one mammal polyploidy called argentenian rat
Theory of inheritance 1 by Artisole (384 BCE)
It was the first widely accepted theory of inheritance called pengensis. The egg and speed consist of particles called pangenes, from all parts of the body.
Theory of inheritance 2 (1667) Anthony Van Leeuwenhoek
He discovered living sperm in semen. He believed he saw a complete miniature person in the head of sperm. Came from father developed in mother.
Theory of inheritance 3 (1800)
It was believed offspring would have characteristics of both parents. They thought the characteristics would blend somewhere in the middle. They believed that original characteristics of the parents could not be perfectly passed down to offspring.
Who was Gregory Mendel
Gregory Mendel (1822-84)was an Austrian monk that studied botany and mathematics at the university of Vienna before entering the monastery.
Why was Gregory Mendel so successful?
He used his knowledge in botany and mathematics. He also chose a pea plant. Pea plants were available in many varsities and show different traits. He also took advantage of the fact that pea plants can produce sexually but can also self fertilize. He used this to insure that the plants he studied were pure bred. He true bred through selective breeding. He used a paint brush to control his experiments so he could breed certain plants with others. (Cross breeding )
What is a genotype
The combination of Alleles for any given trait, or genetic make up.:
What is a phenotype
It is the actual visible and physical characteristics of an organism
What is a monohybrid cross
A monohybrid cross is a cross in which both parents are heterozygous for a single trait.
(Rr,Rr)
Genotypic ratio 1:2:1
Phenotypic ratio: 3-1