• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Write an essay on the functions of proteins in plants and animals

Extracts from this document...


Write an essay on the functions of proteins in plants and animals Proteins are polymers of monomers called amino acids. Amino acids contain hydrogen, carbon, oxygen and nitrogen. When amino acids are linked together, they form polypeptide chains and bonded together by peptide bonds. There are different structures of polypeptides primary, secondary, tertiary and quaternary. The primary structure is a straight chain of polypeptides. Secondary structure is the polypeptide chain coiling to form an ? helix or the polypeptide chain linking together to form a � pleated strand. In an ? helix hydrogen bonding forms in the secondary structure between the NH group of one amino acid and the CO group of another amino acid. In a � pleated strand hydrogen bonding occurs between the CO and NH groups of one amino acid residue of one chain and the NH and CO group of another chain. The further folding of the polypeptide chain is known as the tertiary structure. In this structure the folding and coiling of the chain is irregular. ...read more.


Rubisco found in plants allows Ribulose Bis Phosphate to catalyse carboxylation in photosynthesis. Some hormones are also globular proteins. These too have to be soluble so that they can be transported in the blood plasma. Insulin which is a globular protein with a quaternary structure. Its function is to stimulate the conversion of glucose into glycogen when the level of glucose in the blood plasma is higher than normal. Its counterpart glucagon stimulates the breakdown of glycogen into glucose when the level of glucose in the blood plasma is lower than normal. Adrenalin is also an hormone which vasodilates and vasoconstricts the blood supply to parts of the body which require more or less blood for example during exercise where the skin requires less blood but the skeletal muscles requires more in order to allow contraction of muscles. Proteins are also found in membranes. There are two types intrinsic and extrinsic. The main function of intrinsic proteins is to transport globular proteins. Whereas the extrinsic consists of glycoproteins. ...read more.


Collagen is important and found in the skin and tendons. Collagen cannot be stretched but it highly flexible. This is because the ? helix chain can be stretched but recoils when relaxed. Keratin is also a fibrous protein its function is to make the skin, hair and nails waterproof. Other functions of proteins can be contractible such as myosin and actin which are found in the skeletal muscles. They also make up some of the pigments found in plants and animals. In animals, opsin is found in both rodopsin and iodopsin which allows animals to see objects in colour or black and white and is found only in the eye. Melanin found in mammals is a pigment which gives the skin colour. Phytochrome is found in plants. This protein allows the conversion of P730 into P660 or vice versa depending on the amount of far-red or red light present. This results in the stimulation or inhibition of flowering. Many proteins are required in plants and animals to ensure that they function efficiently. Proteins are needed for many vital processes. Every protein has its own function within plants and animals varying from structural to homeostatic control. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

3 star(s)

The scientific content is almost all relevant to the title and most of the key types of function are covered. However, more precise use of biological language would improve the quality and accuracy.

Marked by teacher Adam Roberts 05/09/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Affect Of Varying Salt Concentration on Red Blood Cell Haemolysis

    4 star(s)

    placed it in the test tube containing the 0% sodium chloride solution. And immediately started the stopcock, I allowed a two minute gap before adding the blood to the next test tube containing 0.1% sodium chloride (blood was mixed again)

  2. Peer reviewed

    The Importance and Biological Functions of Carbohydrates.

    4 star(s)

    Skeletal muscle for energy during resting conditions; however, the brain cannot afford the same luxury. Fatty acids are too long and bulky to cross the blood-brain barrier. Therefore, proteins from various body tissues are broken down into amino acids and used by the liver to produce glucose for the brain and muscle.

  1. The Effect of Different Substrates on the Rate of Respiration on Yeast (Saccharomyces cerevisiae).

    A bung was then placed over the top and a thermometer inserted through into the flask. 10cm3 of the substrate (either glucose, sucrose or lactose) were measured out using a syringe and placed into the top of the bung. A trough was filled up with water and a 500cm3 measuring

  2. heart essay

    Once the blood has been oxygenated by the lungs it is received by the left atrium via the pulmonary vein. It then goes through the bicuspid valve between the left atrium and ventricle, then through the aortic valve between the left ventricle and aortic artery and out to the head and arms, and the lower body and legs.

  1. The mechanism of Negative feedback.

    being the rise of fall of temperature, which gives a greater degree of control. The corrective mechanism is the key component of homeostatic control. Homeostasis is a dynamic process; works by making continual adjustments to compensate for fluctuations of output.

  2. Kidney Function.

    Immediately below the capsule is a twisted region called the proximal convoluted tubule. This leads into the long, hairpin-like loop of Henle, which runs deep into the medulla and then back out of the cortex, where it forms another twisted region called the distal convoluted tubule.

  1. Homeostasis In Mammals.

    This process is somewhat ineffective in humans. Vasoconstriction, is another way in which mammals try to maintain body heat, this is where muscles in the walls of arterioles contract, this causes less blood to flow to the surface of the skin and extremities, maintaining body heat to the vital organs in the centre body mass.

  2. Investigate one factor that affects the rate of respiration of yeast

    The increase in concentration of glucose has therefore contributed to increase in rate of respiration. More concentrated solutions contain more particles in the same place, making them more likely to collide (in this case collide and fit in the active site of the enzymes).

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work