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1. These are simple, single-celled bacteria.

2. The DNA is not within a membrane.

3. DNA is not bound to any protein.

4. Does not have true nucleus. Simple DNA chain that joins to form a circle.

5. Does not have membrane-bound organelle such as mitochondria.

"They do not have homologous pairs of chromosome. Their genotype is shown by what they look like. In other words, what their phenotype is their genotype."


1. All cells other than bacteria or unicellular organism that have a true membrane.

2. Chromosomes are within a nuclear membrane.

3. Is a length of DNA folded. It wounds around proteins called histones.

4. Contain membrane-bound organelles and form spindles dring mitosis and meiosis.

"These might have diploid or haploid number of chromosomes, so their genotype might not be entire expressed in the phenotype "


Main structural chemical of the body/ help to run. (using enzymes and hormones)

What is proteins?

  • Enzymes that catalyse all biochemical reaction.
  • Structure of body (hair and muscles).
  • Carriers of oxygen (haemoglobin).
  • Fight diseases (anti-bodies).
  • Important part of cell membrane.
  • Chemical messenger.


It works by bringing together 2 active sites of 2 chemicals and joining them together via the active site of the enzyme, thus forming an enzyme-substrate complex. Shape is determined by order of amino acids in proteins.

1. Biological catalysts- they speed p the reaction NOT change the direction. They do this by lowering the activation energy required to start the reaction to enable the reaction to occur.

2. They are specific which means that they are able to work more efficiently and quickly. They use a lock and key system. One enzyme is specific to one substrate.

3. They can be affected by temperature. This means that if the temperature decreases, so does the rate of enzyme reaction. In order for the enzyme to work at its best it must be under it optimal temperature. For example, the optimum temperature for human base enzymes is 37 degrees. If any higher the enzyme cold come to be denatured, therefore useless. 

4. It can also be affected by the pH levels. Each enzyme has a specific pH level at which they work the best. For example, the enzymes in the mouth work best at neutral levels while the ones in the stomach work best in acidic situations. 

5. Enzyme concentration/ substrate concentration both affect rate of enzyme action. An increase in either will cause an increase in rate of enzyme action. 

6. Enzymes can also acts as poisons if they are in the worn body part. For example snake venom attacks the blood cells and tissue. 

7. Enzymes + cofactor (metal) = co-enzyme. The cofactor is another substrate that enables the enzyme to break down the given substrates. 

  DNA Functions

1. Carries the genetic code for proper functioning of the organism.

2. ABility to replicate therefore life can continue.

3. DNA is like a string of breads- each bread is represents a gene. Genes are position in set places along the…


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