Hard things to remember

What does does Vitamin A do?

Improves vision, keeps skin and hair healthy

What does vitamin C do?

Prevents scurvy

What does vitamin D do?

needed for calcium absorption, prevents rickets

Where is Vitamin A found?

Liver

Where is vitamin C found?

Fruits, e.g. oranges

Where is vitamin D found?

Eggs

What does bile do?

Is alkaline and neutralises stomach acid, and emulsifies fat

Define peristalsis

waves of circular muscle contractions

What do phagocytes do?

Ingests pathogens by engulfing and digesting them

What do lymphocytes do?

Detects pathogens and produces antibodies

Describe the eye reflex in bright light

Circular muscle contracts, pupil gets smaller/narrows, less light enters the eye

Describe the eye reflex in dim light

Radial muscle contracts, causing pupils to dilate, letting more light in

Describe the eye reflex when focusing on distant object

ciliary muscle relaxes, suspensory ligaments pull tight, lens becomes flat/less curved, so less light is refracted

Describe the eye reflex for focusing on near objects

Ciliary muscle contracts, suspensory ligaments slacken, lens become more curved therefore more light is refracted

Why are nitrates needed in plants?

To make amino acids and proteins for cell growth, else growth will be stunted and older leaves will turn yellow

Why are phosphates needed in plants?

Contains phosphorus for making DNA and cell membranes, as well as for respiration and growth, else plants will have poor root growth and older leaves will be purple

Why is potassium needed in plants?

They help enzymes needed for photosynthesis and respiration, else plants will have poor flower and fruit growth, and discoloured leaves

Why is magnesium needed in plants?

Needed to make chlorophyll for photosynthesis, or plant will have yellow leaves

What does xylem transport?

Water and mineral salts in a transpiration stream

What does phloem transport?

sucrose and amino acids by translocation

Describe the stages of mitosis

Firstly, the cell duplicates its DNA to form x-shaped chromosomes, where each ‘arm’ is a duplicate of one another. Then, the chromosomes line up and cell fibres pull the two arms to the opposite ends. Membranes form around each sets of chromosomes which become the nuclei, and then the cytoplasm divides. This form two new cells which are genetically identical

What cells does mitosis produce?

Two diploid cells

Describe the stages of Meiosis

In the first division, DNA is duplicated and one arm of each chromosome is the copy of the other arm. After lining up in the centre, the pairs are pulled apart and the parents’ chromosomes mix and go into each new cell, causing genetic variation. In the second division, chromosomes line up at the centre, and like mitosis, its arms are pulled apart, giving four haploid gametes, each with a single set of chromosomes

What cells are produced by meiosis?

Four haploid gametes, each with a single set of chromosomes and genetically varies

Biuret Test colour chanage

blue to pink to purple