science 10 gladstone
Friday, 17 January 2025
Pon Farr
Wednesday, 15 January 2025
Wednesday, 8 January 2025
x - linked genes
SEX LINKED GENES
The sex chromosomes are XX and XY in humans. Some alleles are located on the X chromosome. But very few on the Y chromosome. Remember that people who are females have the genotype XX and people who are males have XY.
The Y chromosome carries very little information, only enough to influence the embryo on the path towards male primary and secondary characteristics.
Meanwhile, many RECESSIVE ALLELES are located on the X chromosome, including
1. hemophilia, the inability to clot blood
2. colourblindness inability to tell the difference between red and green colour
3. baldness
These characteristics are far more common in people with male sex organs than people with female sex organs because people with male organs have only one X. And if that X contains the recessive allele, they will show the phenotype. Meanwhile,people with female organs may have the recessive and their dominant genes on their other X will protect them. For example
Some things to note about sex linkage: Signs of sex linked alleles are:
1. more genotypic males get the phenotype, but genotypic females can be carriers
2. males can inherit from mother but not father (because males get their X from mom)
3. genotypic females have an extra X and this protects them. Females must be homozygous to show the sex linked phenotype.
Further reading on sex linkage here http://learn.genetics.utah.edu/content/pigeons/sexlinkage/
FYI if you were born a male and you want to know if you're colourblind: Test yourself here: But careful, if you are a genetically male, you might find out you are colour blind! Apparently most people find out they are colourblind from their science teacher !
http://colorvisiontesting.com/home.html
That Dress! and the science of perception
There is a very interesting dress. It has caused major arguments! This dress causes your cells in your retinas to perceive it to be certain colours depending on the state of your retinas. Of course your genes determine what your retinas are like...but also your retinas change over time too!
Your perception is also based on whether you think this dress is in shadow or light...Try this,
I would like you to ask 20 people you know "What colours do you see on this dress: Is it :
A. GOLD AND WHITE
B. BLACK AND BLUE
C. GOLD AND BLUE
D. NONE OF THE ABOVE...THEN what colour is it?
What are the characteristics of the people who are more likely to say that it is any of the choices above?
Remember you can poll people without meeting face to face. Ask a variety of people including old, young, male, female...put your results on a table and hypothesize why people see different colours
Monday, 6 January 2025
Introduction to Genetics
Watch my introduction to Genetics video and make notes on it.
Answer these questions on this worksheet on A SEPARATE PAPER in ink, or TYPED. ANSWER IN COMPLETE SENTENCES.
Clover Genetic Variation
We know that plants are important to the ecosystem because they photosynthesize. Did you know that some plants are legumes and these are special because they have ROOT NODULES which are nitrogen fixers. These root nodules are little rooms where Rhizobium bacteria convert nitrogen gas into ammonium and then Nitrobacter bacterium in the soil converts ammonium into nitrates. Plants can absorb nitrates to make plant protein. When those plants are eaten by animals, then animals use the nitrogen to make animal protein. You can say that all the protein on your body (muscles, enzymes, hair, fingernail etc) was built from nitrogen which was fixed by Rhizobium at some point in time.
ASSIGNMENT: 10 points
Only certain plants contain these root nodules...amongst them are bean plants and clover plants. Look at the morphology of clover plants below. Look on our school grounds and find AS MANY DIFFERENT GENETIC VARIETIES as you can. Upload your clover pic on a doc or ppt and hand in.
Thursday, 19 December 2024
DNA extraction lab
MODIFICATIONS: USE ONLY ONE STRAWBERRY. And cut the recipe for the extraction liquid in half.
CRUSH THE STRAWBERRY MIXTURE FOR AT LEAST 5 MINS