Objectives To gain an understanding of the structure of the new A level course To have a go at an A level practical Locate the summer task Feedback and Expectations GCSE WWW amp EBI Alevel expectations ID: 636802
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Yr 12 Biology Taster lesson
Objectives:To gain an understanding of the structure of the new A level course To have a go at an A level practical Locate the summer taskSlide2
Feedback and Expectations
GCSE WWW & EBIA-level expectationsSlide3
Your handbook and transition guide can be found on the W Drive.
W Drive Science KS5 Biology Yr 12
Yr 12 Taster Lesson Slide4
Overview4hrs contact plus 4hrs private study per week.
No assessed coursework.18x Core practical activities (CPACs) that make up a practical endorsement. Regular assessment. 3x 2 hour exam papers (2019). 4x topics each year (see handbook). Slide5
FAQCourse structure
Expectations 4hrs contact/4hrs privateTextbook sign upA-level booklet (W-drive)18x Core practicalsLab bookAssessment after 4 weeks, mid topic and end of topicInterventions by classroom teacher plus Yr 12 JLE, Yr 13 MLWGCSE Grade B (Below that historically struggle)
Double scientists can catch up over summer (W-drive)SNAB resources, support and structurePossibility of workshops, summer schools, work exp., trips etcRevision guides via SQUIDSlide6
Summer task
ChallengeComplete the baseline assessment and bring in to your first lesson back after summerSlide7
Gametes, fertilisation and gene expression in plants.
We need to be able to dissect, make observations, identify and label plant structures in a number of lessons in year 12. Plant fertilisation, growth of pollen tubes and gene expression. Importance of plants Seed bank AttenboroughSlide8
Flower Dissection
Pg 113 and 133Dissect a flowering plant.Identify, draw and label Sepals, Petals, Stamen and Carpels. Take a carpel and dissect further to identify the style, ovary and if possible the ovules
EXTENSION If time observe the growth of pollen tubes from pollen grains in the samples provided under a microscope. Slide9
Dissection and Scientific Drawing
Learning outcomes You will:
Observe the structure of a flower
Observe, dissect and record the floral parts of that flower
Prepare a longitudinal section of a flower
Produce an annotated scientific drawing of the longitudinal section of the flower
Understand how the structure of the flower is adapted to its function.Slide10
Dissection and Scientific Drawing
Health and Safety
CLEAPSS
Student Safety Sheet 74
provides information about assessing the risk posed by plant material
.
Many
plants contain toxins. To minimize any potential
risk
,
inform your teacher if you are aware of allergies to a particular plant so that it can be
avoided.
The
pollen of some lilies stains clothing. Wear a lab coat to protect your clothes.
Take
care when using sharp instruments such as
single-edged (safety) razor blades, scalpels
, scissors and mounted needles and follow the instructions for their safe use that have been given to you by your teacher
.
When drawing it is important to take regular breaks to avoid eye strain and damage to the wrist and back. A short rest from drawing every half hour is a good idea.Slide11
Generalised structure of a flowerSlide12Slide13Slide14
Parts of an Alstroemeria flowerSlide15
Cutting a longitudinal section through a flowerSlide16
Common drawing errorsSlide17
Common drawing errorsSlide18
Scientific drawingSlide19
Fully annotated scientific d
rawingSlide20
SEM of pollen grains and pollen tubes. Whilst carrying out your flower dissection try to observe and draw pollen tubes growing from pollen grainsSlide21
How many parts can you identify from memory? Slide22
How many parts can you identify from memory? Slide23Slide24
Pollen Tube Growth
InvestigationsAre the pollen grains all the same? Make a sketch of half a dozen pollen grains. Work out a way of estimating the size of a pollen grain. Compare your results with those obtained by other members of the class.
Leave the pollen grains for one hour, but look at them down the microscope from time to time. Describe and measure any changes which you see. Compare your pollen grains with those set up by other members of the class.
Design a way of measuring the rate at which the pollen tubes grow. Record your results.
Do all pollen tubes grow at the same rate?
Go back to the flowers. Measure the distance from the stigma to the bottom of the ovary in ten different flowers. Compare the distance with the length of your longest pollen tube. Is it a fair comparison?
Why do you need to measure more than one flower and more than one pollen tube?Slide25
Pollination
When a pollen grain is released from an anther, it is partially dehydrated. If it lands on the surface of a stigma of the same flower (self-compatible) or of a different flower of the same species (self-incompatible), it rehydrates. Some species produce flavinols in both the pollen and anther, which is necessary for growth. Mutant maize plants that are deficient in the enzyme that synthesises flavinols are self sterile. Addition of flavinols
restores the ability of the pollen to grow and fertilize the ovules of the female plant.As pollen tubes grow, callose plugs are produced close to the aperture of the pollen grain, so the cytoplasm becomes concentrated towards the growing tip