Download Yr 12 Biology Taster lesson

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 task
Feedback and Expectations
GCSE WWW & EBI
A-level expectations
Your handbook and transition guide can be
found on the W Drive.
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 W Drive
 Science
 KS5
 Biology
 Yr 12
 Yr 12 Taster Lesson
Overview
• 4hrs 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).
FAQ
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Course structure
Expectations 4hrs contact/4hrs private
Textbook sign up
A-level booklet (W-drive)
18x Core practicals
Lab book
Assessment after 4 weeks, mid topic and end of topic
Interventions by classroom teacher plus Yr 12 JLE, Yr 13 MLW
GCSE Grade B (Below that historically struggle)
Double scientists can catch up over summer (W-drive)
SNAB resources, support and structure
Possibility of workshops, summer schools, work exp., trips etc
Revision guides via SQUID
Summer task
Challenge
Complete the baseline assessment and bring in
to your first lesson back after summer
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 Attenborough
Flower Dissection
Pg 113 and 133
• Dissect 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.
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.
Generalised structure of a flower
Parts of an Alstroemeria flower
Cutting a longitudinal section
through a flower
Common drawing errors
Common drawing errors
Scientific drawing
Fully annotated scientific drawing
SEM of pollen
grains and pollen
tubes. Whilst
carrying out your
flower dissection
try to observe and
draw pollen tubes
growing from pollen
grains
How many parts can you identify from memory?
How many parts can you identify from memory?
Pollen Tube Growth
Investigations
1. Are the pollen grains all the same? Make a sketch of half a
dozen pollen grains.
2. Work out a way of estimating the size of a pollen grain. Compare
your results with those obtained by other members of the class.
3. 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.
4. Design a way of measuring the rate at which the pollen tubes
grow. Record your results.
5. Do all pollen tubes grow at the same rate?
6. 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?
7. Why do you need to measure more than one flower and more
than one pollen tube?
Pollination
1. 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 (selfincompatible), it rehydrates.
2. 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.
3. 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