Additional Biology Smart Teach - PowerPoint Presentation

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Additional Biology Smart Teach 2: CellsSlide2

Animal, Plant and Bacteria Cell

OrganellePlant CellAnimal CellBacteria CellNucleusCell MembraneCell WallSap VacuoleFlagellum/PiliPlasmidChloroplastSlide3
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Plant and Animal Cells

7 OrganellesFunctionCell MembraneControls movement into and out of the cell. NucleusContains DNA. Controls the cellCytoplasmWhere chemical reactions take place. MitochondriaWhere respiration occurs.Cell WallMade of CELLULOSE. Supports the cell. VacuoleContains CELL SAP. Helps support the plant by keeping the cell rigidChloroplastContains CHLOROPHYLL. Absorbs LIGHT. Where photosynthesis takes placePlant and animal cells can be studies in greater detail using a light microscope. Light passes through a thin slice of the specimen. Lenses magnify the specimen many times. Slide6

Differences between the cell

PlantAnimal BacteriaNucleusNucleusNo nucleus – chromosomal DNA and PlasmidsCell wallNo cell wallCell wallChloroplastsNo ChloroplastsNo chloroplastsMitochondriaMitochondriaNo MitochondriaNo Slime coat/capsuleNo Slime coat/capsuleSlime coat/capsuleNo piliNo pilipiliNo flagellumflagellumflagellumSlide7

Cell division

Two types resulting in different cells:Mitosis MeiosisYou could be asked to compare and contrast the two processes, or you could be asked to describe in detail one process with a diagram.Slide8

Copy the table and use the information on the following slides to compare mitosis and meiosis

MitosisMeiosisSlide9

Mitosis

Key wordsGrowthCell repairDiploid – 46 chromosomes2 daughter cells which are genetically identical Slide10

Meiosis

KeywordsGametesHaploid – 23 chromosomes4 genetically different daughter cellsSlide11

Now lets have a look at an exam question about this..........Slide12

Questions

Q1.Corals are animals that live on the sea bed.The photograph shows some species of coral. After fertilisation, mitosis takes place to form an embryo.

The embryo develops into new coral.

(i) Describe mitosis.

(3)

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Answer Acceptable answers Mark (i)A description including three of the following points: · cell divides / cell division / cell splits(1) ·

two cells produced (1)

·

(both) diploid (1)

·

(both) cells are

genetically

identical (1)

          credit correct reference to stages of mitosis:

DNA replication / chromosomes duplicate (1)

Chromosomes line up along the equator / middle of the cell (1)

chromosomes pulled to either end of cell (1)

cytokinesis

/ cytoplasm splits (1)

(3)

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Cloning

Process by which organisms are copied exactly.Can apply to plants (taking a cutting)Can apply to animalsYou could be asked to describe the stages of cloning, or evaluate cloning. Evaluating means giving the advantages and disadvantages.Slide15

Stages of cloning – Nuclear transfer

Remove the nucleus from an unfertilised egg cell.Transfer the nucleus from the adult body cell (somatic cell) of the organism you wish to clone into the egg cell. Apply an electric shock to cause the egg cell to begin to divide Implant the embryo cells into a host mother. Slide16

Dolly the Sheep – First cloned mammalSlide17

Advantages and disadvantages

Advantage or disadvantageCloning situationAdvantageAll the new organisms are genetically identical – they will all have the desired characteristics.AdvantageOrganisms that are difficult or slow to breed normally can be reproduced quickly. DisadvantageIf a clone is susceptible to disease or changes in environment, then all the clones will be susceptible.

Disadvantage

It will lead to less variation, and less opportunity to create new varieties in the future.Slide18

Now lets have a look at an exam question about this..........Slide19

*

(ii) A cloned animal contains genetic information that is identical to its parent.  Describe the stages in the production of a cloned mammal.(6)Slide20

Did you get all these points into your answer?

A description including · use of body cell· nucleus removed from body / parent cell· use of egg cell· nucleus removed from egg cell/enucleated egg· nucleus (from body cell) transferred to enucleated egg· electric shock;· to stimulate cell division· mitosis· formation of embryo;· embryo implanted· into surrogate Slide21

1 - 2

· Limited description of 2 of the stages involved in cloning and the sequence of events is confused· the answer communicates ideas using simple language and uses limited scientific terminology· spelling, punctuation and grammar are used with limited accuracy 3 - 4 · a simple description of 3 or more of the stages involved in cloning but some of the steps may be missing or out of sequence· the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately· spelling, punctuation and grammar are used with some accuracy 5 - 6

·

a detailed description of 5 or more of the stages involved in cloning but the sequence is largely in order and complete

·

the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately

·

spelling, punctuation and grammar are used with few errors Slide22

Genetic engineering

This is altering an organisms genetic code to give desired characteristics such as resistance to disease in crops or producing desirable products such as insulin. You could be asked about the stages of genetic engineering and give examples.Slide23

Examples of GM organisms

GM insulinGolden rice that produce extra beta carotene that is used to make Vitamin AHerbicide resistant crop plantsSlide24

Stages of genetic engineering

Select the desired characteristic.Isolate the gene responsible for the characteristic.Insert that gene into another organism usually by using a bacterium as a vector.Replicate the transgenic organism.Slide25

Now lets have a look at an exam question about this..........Slide26

Organisms can be genetically engineered to make them more useful to humans.

Suggest how wheat could be genetically engineered to allow it to grow in wet, marshy land.(3)Slide27

Question

number Answer Mark  an answer describing the process that includes three of the following: identify gene that allows plant to grow in wet or marshy area (1) extract/cut out the gene with a restriction (endonuclease)/enzyme (1) use vector/agrobacterium/ plasmid/to put desired gene into wheat/crop (1) (3)