This document provides an overview of key concepts for a Level 2 Certificate in plant biology. It discusses the processes of photosynthesis and cellular respiration, explaining that photosynthesis uses carbon dioxide and water to produce glucose and oxygen, while respiration breaks down glucose to produce carbon dioxide, water, and energy. It also covers growth, secondary thickening, pollination, fertilization, inheritance, and transportation within plants. The learning outcomes are to understand these various topics at a basic level.

1. RHS Level 2 Certificate
Year 1 Week 11 –
Review week

2. Learning outcomes
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To identify the end product and waste product of
photosynthesis
To state the equation for photosynthesis in words
To state the equation for respiration in words
To identify the end product and waste products of respiration
To identify the tissue involved in secondary thickening
To describe the process of secondary thickening
To define pollination
To describe the process of fertilization
To state the nature of diploid and haploid cells
To define ‘dominant’ and ‘recessive’ in terms of inheritance and
explain their importance in inheritance
To name the tissues involved in transportation within the plant.
To name and define the processes involved in transportation.

4. Why does a leaf look green?

5. e-

6. Process of Cellular Respiration
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Food (glucose) is broken down using oxygen into CO2 and H2O and
energy is released
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This takes place in the mitochondria
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Carbohydrate plus oxygen  carbon dioxide plus water plus
energy
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C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy (ATP)
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This energy can be stored (as ATP) - to be used later for things like
growth

7. Growth
 Two
factors produce growth in plants: cell
division by mitosis and cell expansion/
elongation.
 Takes place at the meristems (apical and
lateral).
 Mitosis is cell division producing two daughter
cells which are identical to the parent cell that
divided.

8. Secondary Growth
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Occurs in woody perennial dicots
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A ring of vascular cambium (meristematic)
produces secondary xylem (to the inside) and
phloem (to the outside). Several layers of xylem
per growing season, one layer of phloem.
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Wood is the accumulation of these secondary
tissues, especially xylem

9. Annual Rings
 Concentric
rings of secondary xylem
 Alternating bands of early and late wood
 Early wood
–
Xylem cells with large diameter, thin walls
 Late
–
wood
Xylem cells with smaller diameter, thicker walls

10. Pollination and fertilization- overview 1
•Pollination is the transfer of pollen from the
anther to the stigma of the flower
•There are two sex cells in the pollen grain
(each with one set of chromosomes – half the
usual number). One cell from the pollen grain
forms a pollen tube. The pollen tube grows
down the style.
•The second cell divides into two identical cells–
one new cell becomes the tube nucleus which
‘drives’ the pollen tube.
•The remaining cell divides again to produce
two haploid sperm cells

11. Pollination and fertilization- overview 2
•The pollen tube finds a tiny opening in
the ovule and enters it
•The two sperm cells enter the ovule- in
the ovule are a diploid cell called the
polar nucleus and a haploid female
gamete
•One sperm cell fuses with the diploid
polar nucleus – this forms the triploid
endosperm
•The other fuses with the haploid female
gamete and forms the zygote (the new
plant embryo) which is diploid

12. Inheritance 1
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Gametes are produced in the ovary and anthers. They
are haploid (contain only one set of chromosomes).
Each will contain a random mix of genes from the
plants parents.
When fertilization takes place the chromosomes from
the male and female gametes combine to produce a
diploid embryonic plant (Zygote).
Genes exist in diploid cells in pairs (alleles). However
each gene in a pair need not be the same.
If the genes in a pair are the same they are said to be
homozygous. The characteristic that is coded for by
that allele will be visible in the plant.

13. Inheritance 2
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Genes come in two sorts – dominant and recessive.
If the genes in an allele are not the same (also
known as heterozygous) then which characteristic is
seen in the plant depends on which gene is
dominant.
The characteristic coded for by the dominant gene is
the one that is expressed.
A characteristic that is coded for by a recessive gene
will only be seen in the plant if the plant is
homozygous for that recessive gene (both genes in
that allele are recessive).

14. Transportation within the plant
 Diffusion
– movement from an area of high
concentration to one of lower concentration.
 Osmosis – movement of water molecules from
an area of high concentration to one of lower
concentration through a semi-permeable
membrane.
 Transpiration – the diffusion of water vapour
formed by evaporation in the leaves out through
the stomata.

15. Transportation within the plant
 Xylem
– transports water and dissolved
mineral nutrients from roots to leaves.
Mature xylem cells are dead.
 Phloem – transports products of
photosynthesis from leaves to sites of use or
storage. Phloem composed of sieve cells
and companion cells and is living tissue.

16. Learning outcomes
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To identify the end product and waste product of
photosynthesis
To state the equation for photosynthesis in words
To state the equation for respiration in words
To identify the end product and waste products of respiration
To identify the tissue involved in secondary thickening
To describe the process of secondary thickening
To define pollination
To describe the process of fertilization
To state the nature of diploid and haploid cells
To define ‘dominant’ and ‘recessive’ in terms of inheritance and
explain their importance in inheritance
To name the tissues involved in transportation within the plant.
To name and define the processes involved in transportation.