Cellular control Flashcards
1
Q
What is the definition of a Homeobox gene and what type of gene is it?
CHALLENGE: What class is it found in?
A
- Group of genes that contain a homeobox gene
- Is 180 base pairs long and codes for a homeodomain a part of the protein that’s 60 amino acids long.
- Is a regulatory gene since it codes for a homeodomain that binds to DNA and switches genes on or off.
CHALLENGE: Animals, plants and fungi.
2
Q
Can you mention an example that can prove homeobox genes existence?
A
- The Pax6 gene
- Seen in fruit flies, mice and humans.
- When mutated causes blindness in the organisms, due to an underdeveloped retina.
- These findings prove that the Pax6 gene is involved in the development of the eyes in all three organisms.
3
Q
What is the common choice of organism used in genetic research and why?
A
- Fruit flies (Dasophilia)
- Easy to keep, small and have a relatively short life span.
4
Q
What are Hox genes and how many do humans have?
A
- One group of homeobox genes found in animals and involved in the correct positioning of body parts. - regulate apoptosis and mitosis in animals.
- Mammals have four clusters on different chromosomes.
- Humans have 39 in total.
5
Q
Can you give examples of factors that affect apoptosis?
A
- When there’s a homeostatic imbalance that causes stress.
- INTERNAL FACTORS: Can be psychological
- EXTERNAL FACTORS: like light intensity and a change in temperature.
- Proven studies: Thalidomide drug
- Was given to women in the 50’s/60’s for morning sickness but affected hox genes in fetus which resulted in shortened limbs at birth.
- Now used for treatments in cancer since speculated to prevent formation of capillary network that is necessary for a tumour to grow and develop.
6
Q
What are somites?
A
- Animals are segmented and developed in the embryos via somites.
- These somites are directed by Hox genes to develop in a particular way depending on position in sequence.
