Genetics 1.1Demonstrate understanding of

biological ideas relating to genetic variation

MAH – Year 11 2011

Purpose – to gather info about what you may already know about the topic.

Quiet Independent work – What does this mean?

15minsEarly finishers exercise included

Pre – Assessment

Giants: http://www.youtube.com/watch?v=7jJq6y4pdPA&feature=channel

Genetics is the study of heredity. We share similarities with our relatives. But when someone says, you have your fathers eyes, you don’t actually have them right. So what do you have?

What gets passed on is a code in the form of DNA. This code tells your body how to make itself. You get DNA from your mum and dad.

When we talk about genetics…

GeneticsIs the study of genes and what they do, how

they are passed on from parent to offspring and how they are expressed.

VariationDescribe how all living things are different.

There is variety within the same species and between different species.

Genetics and Variation

DNA stands for Deoxyribo Nucleic Acid Is found in every cell in the body except red

blood cells

Where have you heard of DNA before?What do you think it’s role is?

DNA

Everyone of our cells (except red

blood cells) contains DNA.

DNA is stored in a structure called

the nucleus

The order of chemicals that make up DNA determine what the body makes. It is like an alphabet. By re-arranging the letters you get different

information. By re arranging the letters of the genetic code, you get different traits.

DNA is a chemical that stores information as a code.

This code is instructions for how to make life.

The end result, or what we can see based on the DNA code is called a phenotype (e.g. Tongue roller, hitchhikers thumb)

DNA carries hereditary information from one generation to the next.

Function of DNA

Based on seating plan

Temporary measure

Groups of 3

Write down who is in your group

Lab Groups

1. Sadiq, Henry, Daniel2. Owen, Matt, Jayden3. Jack, Nick, Dante4. Sam S, Liam, James5. Kahui, Sam, Steven,6. Caleb, Tyler, Danyon, 7. Calum,, Mustafa, Erekose 8. To’i, Brad, Logan9. Chris, Geoff, Ryan S10. Sam, Joshua, Liam P

Lab Groups – Year 11

Now we will isolate some DNA from some fruit cells.

Collect instruction sheet.Watch teacher model method.

What is the role of each ingredient used?What does the DNA look like?

Pages XXX workbook

Practical

Relate to Learning objective“Describe the function of DNA”

New terminologyGenetics, DNA, nucleus, inherit, code,

hereditary, phenotype

Next step: Describe the STRUCTURE of the DNA molecule

Review

Collect Homework sheet oneOne technology that involves DNA is cloning.

Your homework task relates to cloning of humans.

Homework

What are the two functions of DNA?

What was the purpose of the detergent and ethanol in yesterday’s experiment?

DO NOW

Learning objectives1) Recall the function of DNA2) Describe the structure of DNA3) Create a model of DNA

Do NowCrossword

10/02

DNA Gene Allele Mutation Genotype Phenotype Gamete Zygote Dominant Homozygous

Heterozygous Pure Breeding Punnet square Pedigree chart Natural Selection Meiosis Adaptive features Recessive

DO NOW – Set aside a whole page and write ALL of these new terms and leave two lines for a definition

Mermaid syndrome◦ http://www.youtube.com/watch?v=IAOhSUQomVg

1) DNA is a chemical that stores information as a code. This code is instructions for how to make life.

2) DNA carries hereditary information from one generation to the next.

What are the 2 functions of DNA?

Who knows?

Recall

The DNA molecule is often called a DOUBLE HELIX.

Why?

Because it is made of 2 (hence the double) strands of DNA and is in the shape of a helix.

DNA Structure

A

A A

A

T

T T

TC GT G

G

G

C

CC A

A G C G C T1

Strand

1 Strand

2 Strands

(Double)

Like a twisted ladder(Helix)

3D model – What are the parts?

Imagine each strand of DNA is made up of many single units, like a chain.

Each single unit is called a NUCLEOTIDE

A

A A

A

T

T T

TC GT G

G

G

C

CC A

A G C G C T

1 NucleotideClick me to go to a website about DNA

All nucleotides have the same structure. The only thing that changes is the base.There are 4 bases, Adenine, Thymine,

Cytosine, and Guanine

Nucleotide

Phosphate

Sugar Base

Flash DNA

DNA and base pairs

The rungs of the DNA ladder are made from pairs of bases.There are four types of bases. They have complicated names so it is easier to use their initials instead.

These bases always pair together in the same way.

How do you think the four bases pair up?

denineytosin

euanin

ehymin

e

DNA and base pairs

Base pairs hold the two strands of the DNA helix together.The rules for base pairing are…

There are millions of base pairs in a DNA molecule that always follow these rules.

A always pairs with T

C always pairs with G

Amazingly, it is the sequence of bases along a DNA molecule that forms the genetic code – it’s that simple!

http://www.youtube.com/watch?v=qy8dk5iS1f0

DNA structure - Clip

Collect and complete cloze and diagram labelling exercise

Paste it into your book

Silent, independent work

3 minutes

DNA structure

What does antiparallel mean in regard to DNA structure?

How many pairs of chromosomes do humans have?

DO NOW

Each strand of DNA is anti-parallel to the other

Strand 1

Strand 2

Students create a model of DNA double helix on whiteboard using laminated nucleotide pieces.

Now

Click me to go to DNAiThen choose “Finding

the Structure” and “Putting it Together”.

1) DNA is described as a double helix. Why?2) What is the name of the single units that

make up DNA?3) What parts make up these single units?4) What are the 4 bases?5) What are the base pair rules?6) DNA strands are anti-parallel. What does

this mean?

Lesson Review – Structure of DNA

Muddiest Point – you have 1 minute, write down one thing from today’s lesson you are most unclear about. Hand to your teacher as you

leave.

Learning Objectives1) Recall the structure and function of DNA2) Build a model of DNA

Do Now:Muddiest Point Questions

Insert date here

Lesson 3

1) What are 2 functions of DNA?2) Describe the structure of DNA?

Direct and Probe question

DNA Structure and Function

You are to work in groups of 3 to create a model of DNA from playdough.

Your model should be detailed;◦ Include at least 10 nucleotides arranged as

complimentary base pairs◦ Show each structure of the nucleotide (phosphate,

sugar, base)◦ Show the anti – parallel direction of each strand

You have the period to complete it – manage your time wisely. The last 10 minutes of the period will be spent presenting your model.

Now

What did you learn today about the structure of DNA?

How did building a model of DNA help your understanding on it’s structure?

If you were to do this again, what would you do differently?

Lesson Review

Learning objectives

1) Explain the relationship between chromosomes, genes and DNA.

2) Explain why chromosomes exist in pairs

Do now:wordfind

Insert date here

There is approx. 2 metres of DNA in each cell.

How does it all fit in??

What are they and how are they related?

If I were to say to you, what is the relationship between cars and metal, what would you say?

If I were to say to you what is the relationship between bricks and a house, what would you say?

Chromosomes, Genes and DNA

http://www.youtube.com/watch?v=eOvMNOMRRm8

23 and me

NUCLEUSCHROMOSOM

E

DNA DOUBLE HELIX

Base Pairs

Chromosomes, are the storage units of DNA. The DNA double helix is coiled tightly to form a chromosome.

A gene is a section of DNA that carries the code for ONE trait.

Below is a length of DNA from a chromosome

A gene is a section of DNA that codes for one trait

We have 2 copies of every chromosome.

Why do you think this occurs?

Chromosomes exist as pairs

One set comes from mum, the other set

comes from dad

Click me to see how you were

made

l

l

l

Sperm carry one set of chromosomes from the father. Sperm are haploid (half

set of chromosomes)

l

l

The egg has one set of chromosomes from the mother. Eggs are haploid (half

set of chromosomes)

After fertilisation, the embryo is diploid. It has 2 sets of chromosomes.

Is a way of visually organising and arranging all the chromosomes into pairs.

Karyotype

Click me to learn more about

Karyotypes and to complete an interactive challenge

Complete the karyotype exercise.

Now

Down Syndrome

Characteristics:

Characteristic facial features, short stature; heart defects

Susceptibility to respiratory disease, shorter lifespan

Pone to developing early Alzheimer's and leukemia

Often sexually underdeveloped and sterile, usually some degree of mental delay.

Down Syndrome is correlated with age of mother but can also be the result of nondisjunction of the father's chromosome 21.

Klinefelters Syndrome

Chromo Number

Species Number of Chromos

Number of Pairs

Human 46 23Fruit Fly 8 4Rat 38 19Pea 14 7Horse 66 33

Learning Outcome: Write a scientific paragraph that defines each of the following terms DNA, genes and chromosomes and explains the relationship between them

Success is when:◦ The correct definitions for DNA, genes and chromosomes are used◦ It is stated that DNA stores information for life ◦ It is stated that chromosomes are made of DNA◦ It is stated that a gene is a segment of DNA that codes for a particular trait ◦ The relationship between DNA and its ‘packaging’ in chromosomes is

stated◦ The correct spelling and terminology is used◦ The paragraph is easy to read

You will write your own paragraph and then assess your neighbours. You will give your partner a mark for each point that is covered and write down one thing you like about your partners essay and one thing that could be improved.

Paragraph Writing – Pair Assessment

Relationship between Chromosomes, Genes and DNA

Why do chromosomes exist as pairs

Karyotype

Lesson Review

Learning objectives1) Describe what an allele is.2) Explain the role of mutations in forming

new alleles

Do now:Collect and complete cloze exercise on

chromosomes, DNA and genes.

Date

.....alternate forms of a gene....

Hitchhikers thumb or not hitchhikers thumbMid digit hair or not mid digit hairDimples or no dimplesBlood types

Alleles have a different DNA sequence

HOW DO ALLELES FORM?

Alleles

What is a Mutation?

.....A change in a DNA base sequence that can not be easily repaired

Can have varying effects based on the type of mutation

Haemoglobin is an important molecule that transports oxygen in the red blood cells and is coded by the gene HbA.

A mutation in the DNA sequence of the Haemoglobin means that in red blood cells it aggregates differently and makes the Red Blood Cells a funny shape (sickle shaped)

These misshapen blood cells obstruct blood flow

Hemoglobin and Alleles

KRT 1.2 the gene that codes for wool strength◦ Important for processing

Many different ‘versions’

Changes in DNA sequence that gets associated to different strengths of wool

KRT 1.2 Alleles

What causes Mutations? MUTAGENS: are agents that causes genes

to mutate

THEY INCLUDE:◦ High energy radiation – cosmic rays, x-rays,

ultraviolet radiation, radioactive decay

◦ Chemicals – formaldehyde, nitrogen mustards, epoxides, nitrous acid, acridine dyes and alkylating agents,

Effects of Mutations

1. Protein changes2. Changing biochemical pathways3. Changes to chromosomes4. Changes in cell division processes

Mutations lead to evolution and variation among a population

What is a mutation? What is a mutagen? Mutations lead to variation in a species –

TRUE OR FALSE?

What does complementary base pairing mean?

DO NOW

In your own words explain the relationship between alleles and mutations

You tube clips – mermaid syndrome

Mutations

The purpose of this task is for you to summarise the most important points of this lesson.

You have 2 minutes

Hand the named piece of paper to your teacher as you leave.

2 minute paper

Cell division process for growth and repair

Mitosis

This single cell is copied repeatedly to form an adult with approximately 10,000,000,000,000 cells – all with exactly the same information.

How does this copying take place?

1.Each chromosome copies its information (DNA replication) and is now called a chromatid.

2. The chromatids line up in the middle of the cell.

3. Half of each chromatid goes to each end of the cell.

4. Two new cells are formed.

MITOSIS

See an animation of

Mitosis

Mitosis!!! A continuous process Chromosomes replicate Chromosomes condense to become visible Nuclear membrane disappears Chromosomes line up in a single file across the

equator Chromosomes separate going to opposite end of the

cell Nuclear membrane reforms The parent cell starts splitting in two Two new cells are formed, each with the same

number of chromos as the parent cell

http://www.youtube.com/watch?v=jrL65nqfS0k&feature=related

If each cell has 46 chromosomes what happens when egg and sperm join together 46+46?

QUESTION??

How many chromosomes?

How many chromosomes are there in human sex cells?

How many chromosomes are there in new human body cells produced by mitosis?

46 chromosomes(23 matching pairs)

23 unpaired chromosomes

23 unpaired chromosomes

How many chromosomes?

Human sex cells have a set of 23 unpaired chromosomes - that’s half the usual number.

Sex cells in animals and plants follow the same rules.

They have half the usual number of chromosomes.

They have a complete set of single chromosomes.

Why is this important for fertilisation and reproduction?

FLASH 6 – Fertilisation

Chromosomes and fertilisation

FLASH 2 – Mitosis drag & drop

Chromosomes and fertilisation

MEIOSISMeiosis is the special type of cell division that creates gametes.

Why is it necessary to halve the amount of information passed on?

Two gametes (one from each parent) fuse to form a zygote.

A child is born

How does meiosis happen?1. Chromosomes double, just like in Mitosis to form chromatids.

2. Half of the chromatids go one way and half the other.

3. Two new cells are made.4. The chromatids divide again to

form four cells. Each with one set of information.

Haploid = 1 set of chromosomes

Diploid = 2 sets of chromosomes

Mitosis /meiosis test

Square dance

What is meiosis?

Meiosis begins with a single cell.

First the cell makes a copy of each chromosome.

Now, there are two stages of cell division…

original cell

firstdivision

seconddivision

4 new cells

How many chromosomes do the new cells have compared to the original?

What is meiosis?

Meiosis produces four new sex cells with half the original number of chromosomes.

Mitosis is also called reduction division. What does this mean?

In animals, meiosis produces ova in females and sperm cells in males.

In plants the gametes produced by meiosis are pollen grains and ovules.

http://www.cellsalive.com/meiosis.htm

Sexual Reproduction and Variation

http://www.cellsalive.com/meiosis.htm

Mitosis Meiosis

Where does it occur?

Function of cell division

Compare parent cell with daughter cells (genetically)

Number of cells produced

Complete the table

Genotypes, phenotypes, and punnet squares

Alleles Traits that you have/don’t have are called

discontinuous characteristics (e.g. Hitchhikers thumb)

Controlled by one gene with 2 alleles

Alleles are different forms of the same gene◦ Dominant (if present always expressed)◦ Recessive (if two present then will be expressed)

Alleles continued..

Inherit one allele from each parent Three ways that alleles can combine

Tongue Rolling Example: Tongue rolling (T) is dominant to non-tongue rolling (t)TTTttt

Genotype is the genetic make up of an individual◦ E.g. Tongue roll alleles are represented by T or t

What are the 3 possible genotypes?◦ TT, Tt, tt

◦ Homozygous

◦ Heterozygous

Phenotype is what the individual looks like

New words

Practise genotypes and phenotypes

6 stations for you to randomly select two alleles to create genotype

Draw insect!!

Make your own Insect!!

How we determine phenotypes and genotypes of offspring (children)

Tongue roller example◦ A homozygous tongue roller (TT) male mated

with a female who could not tongue roll◦ Draw a punnet square to determine the genotype

and phenotype ratios of their offspring

Punnet Squares

This is a monohybrid cross

All possible combinations of gametes can be shown (father can roll TT, mother can’t tt)

The genotype of all offspring can be worked out

Can work out the chances or ratio of any combination occurring in this case:

Genotype 100% Tt Phenotype 100% Can roll

Punnet Square

Mothers egg

Fathers sperm

T T

t

t TtTt

Tt Tt

What are the Genotypes of children?

What are the phenotypes?

Roller, non roller What is the ratio of

phenotypes? 3:1 How can we tell if the

genotype of a tongue roller is TT or Tt?

Punnet Square (T= tongue roller)

Mothers egg

Fathers sperm

T t

T

t ttTt

TT Tt

In humans free hanging ear lobes (F) are dominant to joined ear lobes (f)

A heterozygous male had children with a homozygous recessive female

Draw a punnet square and write the genotype and phenotype ratios

Example

GENETICS PROBLEMSIn humans, blue eyes are recessive to brown:

Dad (bb)Mum (B?) Baby (bb)

Is Mum homozygous for brown eyes? ________ How do you know? (complete the Punnett square)

MICE

In mice, albino (a) is a recessive trait

Big Momma mouse Poppa mouse Stuart Little

Complete the Punnett square to show how Stuart ended up an albino

If there were 8 babies in the litter, how many would we expect to have normal colouring? _________

Breed your insect with another

Insect Activity

THE MONK

Who is this dude?

How about this one?

Gregor Mendel. He is the father of genetics – he is the reason that we can clone sheep, cure diseases and why CSI is on telly. Sort of.

Mendel’s work:

He spent many years studying pea plants, among other things.

He found that they had a large amount of variation in their appearance, and sought to find out why.

Stick in the work sheets on Gregor Mendel and have a go at the genetic crosses

Then have a go at the monohybrid crosses pg. 45

Mrs H has extra questions for you to have a go at

We are nearly finished the content for the US so lets keep up the good work! FOCUS!!

Gregor Mendel

A kind of dominance wherein the dominant gene completely masks the effect of the recessive gene in heterozygous condition

Incomplete e.g. Snap Dragon

Co-Dominac e.g. Spots

Complete dominance

gene

allele

phenotype

genotype

Section of DNA that codes for a particular trait or characteristic.

A different form of a gene that codes for a different version of a characteristic.A description of the pair of alleles present for a characteristic.

The physical expression of the alleles.

What do these genetic terms mean?

homozygous

heterozygous

recessive

dominant

Pair of alleles that produce a characteristic that are the same, e.g. HH.

Pair of alleles that produce a characteristic that are different, e.g. Hh.

An allele that will only be expressed when both alleles are of this type, represented by a lower case letter.

An allele that will always be expressed even when there is only one of these alleles present, represented by a capital letter.

What do these genetic terms mean?

THE MONK

Who is this guy?

How about this one?

Gregor Mendel. He is the father of genetics – he is the reason that we can clone sheep, cure diseases and why CSI is on telly. Sort of.

Mendel’s work:

He spent many years studying pea plants, among other things.

He found that they had a large amount of variation in their appearance, and sought to find out why.

MENDEL AND PEASIn one of his experiments he took the anthers off a purple flower. Why?

To stop it self fertilizing!

He then took pollen from a white flower and fertilized the purple flower.

     

 

                 

He found that 100% of the offspring were purple.

He then took two of the purple offspring and crossed them. What do you think he found?

WHAT CAUSES IT???

VARIATION

Spot the family likeness

Mum Dad

son daughter

Which parent do these children look more like?If the son grows up to have children who might they look like?

Members of the same family often look similar.

Inherited characteristics

Mum Dad

son

Humans, like all living things, inherit characteristics from their parents. How are characteristics passed on?

Why do members of the same family look similar?

daughter

Inherited characteristics

Like all babies, this little boy carries a unique set of genes, half from his mother and half from his father.

This newborn baby’s characteristics are passed in the genes it has inherited from its parents.

Causes of variation

But are your characteristics only affected by your genes?

What ELSE will influence the characteristics of this baby as he grows up?

People are different because they inherit different characteristics from their parents.

Causes of variation

Your upbringing and the environment in which you live also affect how you turn out as an adult!

When he gets older, this baby might support a different football team (like Fulham) or not even like football.

Causes of variation

Differences in some characteristics are due to a combination of both inherited and environmental factors.

Your unique characteristics are caused by:

- the unique set of genes you have inherited from your parents

- the environment in which you have developed.

Causes of variation

Variation in plants

Plants inherit characteristics through their genes just like humans and other animals.

What characteristics have these plants inherited?

Are plants also affected by their environment?

What causes variation in plants?

Plants are affected by four key environmental factors. Can you name them?

Plants are affected by their environment in a big way.

With a little more moisture, light or warmth the size of a plant can double. (Imagine if that happened to us!)

water

sunlight

temperature

nutrients in soil

What causes variation in plants?

Read the information supplied

Based on the discussion we have just had and the readings write a paragraph in your book on variation under the heading’

HERITABLE AND NON-HERITABLE VARIATION

Heritable vs non-heritable variation

Individuals which are heterozygous are called carriers, because they carry a recessive allele.

To find out whether an animal carrying a dominant is homozygous or heterozygous, the animal is mated with a homozygous recessive animal.

This is called a test cross

Test Cross

You should be able to explain the difference between variation that is heritable and variation that is non-heritable

By the end of today...

It is not an adjustment to environment, but is a heritable feature shaped by natural selection, acting on variation, because of the variation's effect on fitness

Complex sentence but we will revisit at the end of this section and you will be able to explain in your own words

Adaptive features

Adaptations are special features or behaviours that make an organism particularly suited to its environment. They are part of the evolutionary process

Ten minutes to look at the various animals/plants and determine their adaptations to the environment

Adaptations

thick fur and body fat insulate from the cold

large, wide feet spread the body’s weight and act as good paddles and snow shoes

white greasy fur repels water and acts as camouflage

How are polar bears adapted?

Other adaptations that polar bears have evolved to cope with conditions in the harsh polar environment include:

eyes have brown irises to reduce the glare from the Sun’s reflection

small ears and small body surface area to volume ratio reduces heat loss

black skin is a good absorber of heat

More polar bears adaptations

camels have three stomachs

Camels are amazing creatures! Did you know that:

Curious camel facts

some camels live to over 40 years old

some Bactrian camels can transport 450 kg

archaeological finds show that camels originated in North America

Somalia is home to over six million camels!

wide feet spread out body weight on shifting sand

How is a camel adapted to life in a very hot, dry climate?

little water is lost through sweating or urination

long, thin legs help to increase body surface area and increase heat loss

fat is stored together in the hump to reduce overheating

How is a camel adapted?

nostrils can be closed for protection during sandstorms

very varied diet, ranging from grass and bark to thorns and bones.

long eyelashes and furry ears prevent sand and dust from getting in

What other adaptations have camels evolved to cope with the harsh desert environment?

More camel adaptations

leaves are narrow spines to reduce water loss and protect from predators

water stored in a fleshy stem, and a thick, waxy surface reduces water loss

How is a cactus adapted to life in a very hot, dry climate?

roots are either very deep, or shallow and widespread to catch surface water

How is a cactus adapted?

How is this shark adapted to an aquatic environment?streamlined shape to reduce friction when moving through water

gills have a large surface area so that oxygen can be extracted from the surrounding water

silver colouring allows the fish to be camouflaged

Aquatic adaptations

fins provide stability, power and control

Living things that are well adapted to their environment survive and reproduce. Those that are not well adapted don’t survive and reproduce. An adaptation is any characteristic that increases fitness, which is defined as the ability to survive and reproduce.

Summary

Explain the theory of natural selection using words such as environment, selecting, phenotypes

Give one example of natural selection in action

You will be able to .....

...is the environment selecting FOR or AGAINST certain PHENOTYPES

phenotypes: structure, metabolism, behaviour, physiology environment factors: predators, competition, disease,

lack of food, light, water, climate factors

..possess adaptations such as ability to avoid predators or to compete strongly for food

RESULTS IN: An increase in the allele frequency of those that aid in survival

Natural Selection

Natural Selection Simulation

Read the information on natural selection and alleles and summarise the information on the paper provided

Stick into your book

Readings on Natural Selection

Explain the process of natural selection in regard to the peppered moth

Use words like: Phenotype, predators, genotypes, allele frequency

Once finished make sure all the problems in your work book are done for genetics

Then I will give you some exam ??’s to have a go with

In your own words…

What does complete dominance mean

Name three phenotypes that could be selected for in relation to natural selection

e.g. camouflage so can’t be seen by predators

What sex chromosomes do males have

What sex chromosomes do females have

DO NOW

Variation within a species becomes very important in a changing environment

Eg. If a new disease arises by mutations, then if all members of a species had the same genes then they would be wiped out

BUT

If some were more resistant then they might survive, and if the resistant phenotype was inheritable then their offspring would also be resistant.

This is how species change or evolve over time

Genetic Variation

Sexual Asexual

Use the handout to fill out the table aboveOnce finished complete the questions on page 80-81 in your work book

Compare and Contrast Sexual and Asexual Reproduction

Selective breeding http://www.youtube.com/watch?

v=rW54_vM9SF0

Genetic Engineering

Cloning

Using the information in your workbook is

Applications of genetics

Describe what selective breeding is

What does a ‘carrier’ mean in relation to complete dominance and alleles

DO NOW

Pedigree Analysis - Book

Look for ‘new’ phenotypes in the offspring of a couple as this indicates the parents are carriers of the recessive allele

Make a decision if trait is recessive/dominant and see if applies to all ‘family’ situations

Sometimes you will be unable to determine the full genotype of an individual you may know if it carries the dominant allele but not if heterozygous or homozygous

How to?