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MODULE 3: SICKLE CELL DISEASE - Coggle Diagram
MODULE 3: SICKLE CELL DISEASE
How are Genes and Chromosomes involved in inheritance?
What are Genes and Alleles?
Genes are basic unit of inheritance. There are 20,000 different genes in their genome.
Cell Division: purpose is to pass a copy of a cell's gene to the next generation
Alleles: a variation gene. They have no real effect on the resulting protein. Example alleles are eye color, blood type or height. Not associated with physical characteristics, but cellular functions. The change in beta hemoglobin chain associated with sickle cell disease an example of allele.
Sexual Reproduction: pass an individual's gene onto the next generation.
What is a Chromosome?
Are composed of DNA and packaging proteins called histones.
Forms nucleosomes, which are compressed together to form a chromosome
Humans and many other organisms are diploid organisms: we have two copies of each chromosomes (one from mom and one from dad). Diploid is abbreviated as 2n (n represents the number of chromosomes
The process of DNA replication makes a copy of each homologous chromosome prior to cell division.
How are Sex Chromosomes Different?
Autosomes: no difference between males and females
Sex chromosomes: difference between males in females (X and Y)
Males chromosome: XY
Female chromosome: XX
The Y chromosome contains a gene called SRY that triggers male characteristics
What is Sexual Reproduction?
What is the Lifecycle of Humans?
the reproductive organs produce gametes (sperm and egg) that contain one copy of each chromosome (haploid). This process is called meiosis
During sexual reproduction, a haploid sperm fertilizes a haploid egg and produces a diploid zygote. The single celled zygote divides by mitosis to produce a multicellular diploid individual.
What is Meiosis?
A form of cell division that reduces the chromosome number of the daughter cells from diploid to haploid and introduce variation into the daughter cells.
Consist of two rounds of cell division and results in the formation of four haploid cells.
Meiosis l
Consist of steps as mitosis: prophase, metaphase, anaphase and telophase. The only difference is that homologous chromosomes have paired with one another.
Meiosis ll
similar to mitosis except that cells starting the processes are haploid.
How are Egg and Sperm made?
Meiosis only occurs in specialized cells in the reproductive system.
Spermatogenesis occurs in the testes. First produce diploid primary spermatocytes. It then divides during the first meiotic division to form two haploid secondary spermatocytes.
Second Spermatocytes divide during the second meiotic division to produce four haploid spermatids, which later mature into sperm cells.
Oogenesis is the term used to describe meiosis in females.