Archive for the ‘G11 HL Biology’ Category

Almost there!

Monday, June 6th, 2011

Claire's cakes by wuperruper on flickr

Just when you thought it was all over …. without you knowing it, we have been working through Topic 10, which is the higher level material on meiosis and genetics.  I am fairly happy that we will complete this before you disappear for a few well-earned weeks of rest.  Here is the syllabus guide for the topic, and a link to the presentation we used in class. IB Biology HL Topic 10 – syllabus guide

This presentation is an excellent review and extension of meiosis.  And this one is all about polygenic inheritance.

Genetic engineering and biotechnology

Thursday, May 5th, 2011

Gel electrophoresis method used to separate the coloured dyes in food colouring by Shandchem on flickr

The last section of work before IB1 exams!  This is cool stuff.  It is the “newest” part of the course as it involves science that is very current.  Here are some of the questions we’ll attempt to answer:-

  • What are the techniques of PCR and gel electrophoresis and how do they work?
  • What is DNA profiling and how can it be used to determine paternity or in forensic investigations?
  • What is meant by “gene transfer” and how can it be performed?
  • What are some examples of genetically modified crops or animals?
  • What are the potential benefits and harmful effects of genetic modification?
  • What is a clone? How can we clone using differentiated animal cells?
  • What are the ethical considerations of therapeutic cloning in humans?

Take a look at these notes: Genetic Engineering And here is a FABULOUS blog post from Mr Taylor with TONS of resources – videos, slideshows, interactive links – you name it, it’s here.  USE THEM!

Theoretical genetics

Wednesday, April 20th, 2011

This is the fun stuff – working out genetics problems.  Before the fun stuff comes the groundwork – learning definitions.  Know the meaning of the following terms.

genotype, phenotype, dominant allele, recessive allele, codominant alleles, locus, homozygous, heterzygous, carrier, test cross, sex linkage

Here is Mr Taylor’s presentation on this section.  Use the links suggested for question practice.  The more problems you solve, the easier they become 🙂

Meiosis

Wednesday, April 13th, 2011

genes on parade by Esthr on flickr

Here are some of the terms we will get to terms with in this section 🙂

diploid, haploid, homologous chromosomes, crossing over, non-disjunction, trisomy, karyotyping

  • We’ll learn about the process of meiosis, and why it is known as a reduction division.
  • We’ll understand how chromosome abnormalities such as Down’s syndrome come about.
  • We’ll learn what a karyotype is and how to analyse one.
  • And we’ll discuss some ethical issues to do with karyotyping of unborn fetuses. 

There are a number of ToK links here, such as balancing the risks of side-effects with preparing for a chromosome abnormality in an unborn child.  There are also questions raised about who should make the decision about whether to perform the karyotype – the parents, doctors, governments?

Here is Mr Taylor’s presentation on this topic.  And here is a very very very dated but well done video.   Biologix__Meiosis_and_Gamete_Formation

We’ll use this site – The Biology Project – to practise karyotyping.

Group 4 project

Wednesday, April 6th, 2011

Group 4 day is coming ….. this year it is on Wednesday 11th May.  The purpose and schedule and requirements are outlined int his presentation:  Group 4 Day powerpoint

You will also receive a version of this handout: group IV project booklet 2011 revised for students  Please go through it carefully.  This is the only time that the IB assesses personal skills, so you get one shot at it.  For an ISM grade we will look at your self-reflection. 

Good luck, have fun, and enjoy being collaborative scientists!

Chromosomes, genes, alleles and mutations

Tuesday, April 5th, 2011

sickle cell anemia by udt007us on flickr

We are about to embark on the last topic of the year!  It’s a great topic – and an important one – all to do with GENETICS.  Here is the syllabus guide: Topic 4 – Syllabus outline

In this first section we need to know what eukaryotic chromosomes are made of, and be able to define the terms gene, allele, genome and gene mutation.  We’ll learn about the disease sickle-cell anemia – how it is caused by substitution of a single base in the gene for making haemoglobin.  This will be a good review of transcription and translation [remember them?] as well.  Here is Mr Taylor’s presentation covering these points.

Click here for an excellent blog post that will help you understand how all this connects together.

Reproduction in flowering plants

Wednesday, March 30th, 2011

White flower by doug88888 on flickr

Flowers are the reproductive organs of angiospermophytes.  You will get the chance to disect one, and to draw and label it.  Some flowers are pollinated by wind, others by insects.  We’ll focus on the insect pollinated ones in this topic.  You will also need to be able to distinguish between these three processes:- pollination, fertilization and seed dispersal.

We’ll then take a look at seeds and seed structure, and the process of germination.  Finally we will learn about phytochromes and their role in controlling flowering in long-day and short-day plants.  Read about photoperiodism here.

Be prepared to do some independent reading from your textbooks on this topic.  Here is Mr Taylor’s presentation.  And here is another useful one. Reproduction in angiospermophytes

Transport in plants

Thursday, March 17th, 2011

Cactus series by PVCG on flickr

Here is Mr Taylor’s presentation on this topic.  Transport in angiospermophytes

  • How do water and mineral ions enter a plant?
  • How does water move upwards, against gravity, in a plant stem?
  • What is transpiration and what are the factors that affect it?
  • How are plants adapted for particularly dry or wet environments?

We will also set up a lab to investigate which surface of a leaf transpires the most, and learn what a potometer is and how to use it.

Plant structure and growth

Thursday, March 10th, 2011

twig and tendril by stonebird on flickr

As we embark on topic 9, here is the syllabus outline: Topic 9 – Syllabus outline

This topic can be broken into 3 sections:  structure and growth, transport, reproduction.  This document has notes on all of this. Plant Science Topic notes

We’ll start with plant structure and growth.  Plant structure & growth  Here is Mr Taylor’s presentation on this section.

Some things we’ll discover in this section:

  • why do plants grow towards light?
  • how can you tell if a plant is a monocotyledon or dicotyledon?
  • how can plants modify their roots, stems and leaves for different functions?

Photosynthesis

Friday, February 18th, 2011

Jatropha hybdrid - leaf detail by tonrulkens on flickr

And here is the sing-along song for this topic.

For notes on the SL portion of the syllabus, here is a useful powerpoint.  Photosynthesis  This is the core material from our favourite teacher in Indonesia.  Once you have grasped the basics, move on to this HL stuff.

We’ll cover a lot of interesting ideas in this unit.  How are plants affected by light of different wavelengths?  What is the relationship between structure and function in chloroplasts? What is meant by limiting factors in determining photosynthetic rate?  How can we measure photosynthesis?  And, of course, we’ll delve into the biochemical pathways of the light dependent and light independent reactions.

Useful video for labs.

There are 3 online photosynthesis simulations that we will use.  This first one is nice and simple and should help get you started on your design lab.  This one is also easy to use.  This third one is more complicated, and you might want to come back to it as we go through the topic.