B2.1 Inside Living cells

Objectives The chemical reactions essential for life take place inside cells Respiring cells require a supply of glucose and oxygen, producing carbon dioxide as a waste product Genes are the template for protein synthesis inside cells The digestive, circulatory and respiratory systems provide cells with the basic materials they need to carry out their functions.

DNA In the nucleus of a cell are chromosomes, made up of genes, made up of DNA. DNA is like a set of instructions, called the genetic code DNA tells the cell to make specific proteins DNA a double helix Click image!

Base pairs Adenine – Thymine Guanine – Cytosine To help you remember: Alan Titchmarsh George Clooney

Proteins Amino acids make up proteins There are 20 amino acids Their order determines the protein that is made DNA unzips and copy of the coding strand of DNA is made, it is called messenger RNA (mRNA) it make a mirror image BUT it uses Uracil (U) instead of Thymine. This is called transcription After the mRNA has detached the DNA winds back up, base pairing G-C to A-T

Each 3 bases make up a code that relates to a different protein There are 20 protein, many of them have a few codes, you do not need to know the proteins! THIS IS A LEVEL work so you do not need to know it, but it makes it easier to understand the triplet system The Genetic code

Translation The mRNA leaves the nucleus and enters the cytoplasm The mRNA is taken to the ribosome It is read by another type of RNA, Transfer RNA tRNA which carries the amino acids This is where triplets (3 bases, I amino acid) attach to the mRNA to make a protein. tRNA molecules continue to bring amino acids until the chain is 10s or 100s long. This is a poly peptide. This now needs to be folded into a particular shape, to make a make it a working structure. Click for video

Insulin is a globular protein. A polypeptide once folded and arranged correctly becomes a functioning protein

Fermentation Penicillin- mould called Penicillium Yeast-bread, beer wine Cheese, yoghurt- lactic acid bacteria Quorn - Mycoprotien Micro-organisms grow very fast they can be kept under controlled conditions and grown in any country to make food.

Fermentation Micro-organisms are cultivated in a culture medium They use up the nutrient s and produce waste products Yeast given sugar, broken into CO 2 and ethanol (alcohol) Fermenters are used to cultivate microbes to make many different products and different nutrients are added to produce different products.

Fermentation Bacteria have DNA like humans So they can be used to make human proteins, like insulin Cut out the human insulin gene, stick it into bacterial DNA, use a fermenter to produce lots of the Bactria which will produce a lot of insulin Click for video

To avoid contamination with other microbes the fermenter but be sterile before anything is added. Aseptic measures must be taken. Usually cleaned with hot steam, under high pressure. Contamination can cause a low yield of product

Aerobic Respiration

glucose + oxygen carbon dioxide + water + energy When you exercise your muscles need more energy, so the rate of respiration needs to increase, you take in more oxygen and get rid of more carbon dioxide by increased breathing rate. Heart beats faster, to take more oxygen away from your lungs to your cells a large concentration gradient is maintained so that gas exchange occurs more quickly.

The effects of exercise More oxygen absorbed by lungs, More carbon dioxide is removed, More glucose and oxygen need to be delivered to your cells This means that your breathing and heart rate will increase

Improving measurements Taking your pulse by hand means you have to take it over time, and stop exercise Digital equipment is more reliable and you can get instant results Our core body temp is 37°C, it only changes by a 1/10 of a degree during exercise, however our surface body temp will change Reliable means that you get the same results every time Precise means that the result are close to the real value

Anaerobic Respiration

Atkins diet

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