Biology as unit 2 revision

They are soluble in organic solvents and have been used extensively as dyes for fabrics. It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions.

This is called a mutation, sometimes the mutation causes tehm to be resistant to an antibiotic, therefore more difficult to kill. Crucial to those studies was the development in the late 20th century of tissue culture methods that allowed for the growth of mammalian embryonic stem cells —and ultimately human embryonic stem cells—on culture plates.

As a cell differentiates it acquires different sub-cellular structures to enable it to carry out a certain function. Flavonoids occur in living tissue mainly in combination with sugar molecules, forming glycosides.

Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. A typical anthocyanin is red in acid, violet in neutral, and blue in alkaline solution.

Perhaps the last of the ancient biological scientists of note was Galen of Pergamuma Greek physician who practiced in Rome during the middle of the 2nd century ce. Stomach enzymes would not work well in the intestine.

Bonus Lectures Please refer to the program brochure for further details.

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Some of the substances transported in and out of cells by diffusion are oxygen and carbon dioxide in gas exchange, and of the waste product urea from cells into the blood plasma for excretion in the kidney.

However, if there isnt enough glucose, your body uses stores of glucose in your muscle and liver cells. The study of structure Living things are defined in terms of the activities or functions that are missing in nonliving things.

The root system anchors the plant and takes in water and nutrients N,P,K. More than one anthocyanin may be present in a flower or blossom, and the colours of many flowers are caused by the presence of both anthocyanins and plastid pigments in the tissues. A red blood cell contains a cytoplasm and cell membrane surrounded by a cell wall with no nucleus.

Biology unit 2

Pump the antibiotic out of the cell Alter the protein on the bacterial cell so the antibiotic cannot recognise it roduce enzymes to destroy the antibiotic 23 of 57 S.

Flavonoids The biochromes in the class of flavonoids, another instance of compounds lacking nitrogen, are extensively represented in plants but are of relatively minor and limited occurrence in animals, which rely on plants as sources of these pigments.

Unit 2 – Development, Plants and the Environment

Indigoids Like melanins, the indigo compounds are excretory metabolic breakdown products in certain animals. The oesophagus carries the insoluble food molecules to the stomach. The characteristic controlled by a recessive allele develops only if the recessive allele is is present on both chromosomes in a pair.

Food is taken from the mouth. The human respiratory system is adapted to allow air to pass in and out of the body, and for efficient gas exchange to happen. Exercise and smoking both affect the lungs and circulatory system. If you started your course in September or later in England, you need the new Edexcel (A) Biology () or Edexcel (B) Biology () pages.

These topics are examined in the IAL Unit 2 paper for Edexcel Biology. You can learn anything. Expert-created content and resources for every course and level. Always free.

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Learn biology revision unit 2 with free interactive flashcards. Choose from different sets of biology revision unit 2 flashcards on Quizlet. Coloration: Coloration, in biology, the general appearance of an organism as determined by the quality and quantity of light that is reflected or emitted from its surfaces.

Coloration depends upon several factors: the colour and distribution of the organism’s biochromes (pigments), particularly the relative. Plant Cells: Like animal cells, plant cells usually have a nucleus, cell membrane, mitochondria, cytoplasm, and janettravellmd.com cells also have a cell wall made of a carbohydrate called janettravellmd.com cellulose is made of tiny fibres, and together these fibres become very strong and support the cell.

Some plant cells also have organelles .

Biology as unit 2 revision
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