Hey guys :). Key knowledge from today: The Human Genome Project:
Our genome is the base sequence of our entire DNA complement of our cells. Phosphate, plus deoxyribose sugar, plus a nitrogenous base = nucleotide. Nucleotides join together to form DNA sequences, these are known as genes, these genes code for proteins. Mutations in this code lead to genetic disorders and diseases... for example, cystic fibrosis. Here is a link to various genetic disorders... https://www.jeansforgenesday.org/educationalresources#ryansstory Here is an interactive of just where the DNA is found in the cell nucleus and what it looks like when you zoom in on it really close... it also shows some proteins that are made from it. http://www.chromosomewalk.ch/en/what-are-we-made-out-of When we think about our nitrogenous bases, we need to remember Chargraff's rule! The proportions of Adenine and Thymine in DNA are about equal and the proportions of Cytosine and Guanine are about equal. YOU'LL NOTICE... that Cytosine and Thymine are similar shapes! We call these Pyrimidines... Adenine and Guanine are also similar, we call these Purines.
Any questions... comment on here or email me :). Miss Barlow.
0 Comments
Chapter 11: Sexual ReproductionMEIOSIS FROM THE BOOK: Haploid gametes (sperm and egg) get together to form the ZYGOTE, remember the zygote is the only totipotent cell! And then the zygote divides, and divides, and divides, BY MITOSIS, to become the BLASTOCYST. The INNER CELL MASS of the BLASTOCYST, is PLURIPOTENT (also known as EMBRYONIC STEM CELLS). EMBRYONIC STEM CELLS differentiate through GASTRULATION to become the THREE GERM LAYERS OF THE DEVELOPING FETUS: -the ectoderm -mesoderm -and endoderm. These differentiate into the different tissues of the body... and in doing so, are now MULTIPOTENT STEM CELLS (also known as ADULT STEM CELLS). Sometimes they take out the INNER CELL MASS (pluripotent stem cells) AND INDUCE THEM TO BECOME ADULT TISSUES! Good idea to have a think about the advantages of sexual vs asexual reproduction... aaaaand, internal vs external fertilization... Have a good weekend guys :). Here's a cool vid of bacteria dividing, remember they replicate their ONE CIRCULAR DNA molecule every time :).
Hey guys,
Here you will find all you need to revise for your Super Test!
Chapter 9: The Cell Cycle
Binary Fission in Prokaryotes:
Here shows asexual reproduction in Bacteria, lets remember it has one circular chromosome, not 23 double helix structures like humans!
Understand the process by which Bacteria divides, in terms of time it takes, how many chromosomes? (one circular one in Bacteria).
Stages of the Cell Cycle in Eukaryotes:
You should be able to draw and identify the key processes that occur at each point in Interphase (G1, S, G2), Mitosis and Cytokinesis! The phases of Interphase are highlighted below, NOTE: That Mitosis only takes 1 hour in the whole 24 hour Cell Cycle... Where does the cell spend most of it's time? Where does amount of DNA double?!
Think about where mitosis occurs in humans?
Look at slides 8, 11 & 12 of the Cells in Action PowerPoint if you need some inspo.
Don't forget about how cancer cells divide differently!
Watch the little cell down the bottom left corner... See if you can identify ALL OF THE PHASES! :D For this reason our Cell Cycle has Checkpoints... Do you know where these occur? What happens at these checkpoints? Chapter 10: Asexual Reproduction:
Must know:
What type of offspring do these processes (Mitosis and Binary Fission) result in? (Genetically identical or not?) Think about it in comparison to Meiosis!?!? And EVERYTHING our big brains know about HOW Meiosis produces Genetic Variation! Specifically the TWO reasons we get genetic variation... (*CLUE: It happens during Prophase 1 of Meiosis when our chromosomes are all messing about in the cell, and all their sista chromatidz get tangled (and our lolly snake chromatids broke off and rejoined), WHAT WAS THIS CALLED? Watch your meiosis video again if you forget... Scroll down for answer... But keep thinking.. Keep thinking... Crossing Over! Yes, that's right. But what else happened?! At Metaphase 1!? Did our chromosomes from Mum's haploid egg all line up on the left side of the equator and Dad's haploid sperm chromosomes all line up on the right? Hmm... Nope... Some went left and some went right... This is known as Independent Assortment!
THESE ARE THE TWO THINGS REQUIRED FOR GENETIC VARIATION AND THIS ONLY HAPPENS IN MEIOSIS. MORE ON MEIOSIS LATER...
But for now... Back to asexual reproduction...
Cloning, think about the two ways this can happen...
Embryo splitting...
We now know the inner cell mass of the blastocyst is what they use for embryo splitting! Because it is a pluripotent stem cell (it can become anything but the...?) Placenta! Here is a picture of the embryo in a petri dish being split, one of those with be planted straight into the surrogate mother!
Or... Somatic Cell Nuclear Transfer...
We used this interactive website to understand how Somatic Nuclear Cell Transfer worked... here's the link.. http://learn.genetics.utah.edu/content/cloning/clickandclone/ This is it happening in a diagram.. Remember the somatic body cell could be any body cell (skin, muscle, blood) and we now know they are multipotent stem cells!
Wowee.. That's probably about enough for now... And That's probably about it for Chapter 9 and 10.
Email Miss Barlow with and questions you might have and she'll keep thinking of things that might help you revise! Stick at it gang! |
Categories |