RHS Level 2 Certificate

Year 1 Week 11 – Review week

Learning outcomes

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.

Why does a leaf look green?

e-

Process of Cellular Respiration

Food (glucose) is broken down using oxygen into CO2 and H2O and energy is released

This takes place in the mitochondria

Carbohydrate plus oxygen carbon dioxide plus water plus energy

C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy (ATP)

This energy can be stored (as ATP) - to be used later for things like growth

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.

Secondary Growth

Occurs in woody perennial dicots

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.

Wood is the accumulation of these secondary

tissues, especially xylem

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

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

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

Inheritance 1

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.

Inheritance 2

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).

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.

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.

Learning outcomes

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.