Unit 2.1 The Human Body Flashcards
2.1.1 Life Processes:
All living things perform essential functions, What are these?
MRS GREN: Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition
2.1.2 Basic Chemistry
What do chemical changes involve?
Chemical changes involve changing the bonds that hold atoms together, they all involve energy transfers.
What is the activation energy?
The energy required to break chemical bonds, supplied by the collision that occur between molecules as they move randomly.
What can affect the rate of a reactions?
The higher the temperature, the more frequently these collisions occur and the faster the rate of reaction
What is released when new bonds form?
Energy
What is an Endothermic reaction?
More energy is taken in from the environment to break bonds than is released when new bonds are made. e.g photosynthesis.
What is an Exothermic reaction?
More energy is released when new bonds are formed than is taken in to break bonds. Exothermic reactions usually warm their environment eg. respiration.
What is the core temperature of a human?
37 degreesC
Due to the relatively low concentration fo molecules inside cells, most chemical reactions needed inside humans would not happen quickly enough to sustain life, what do we have to help with this?
Biological catalysts called enzymes speed up chemical reactions in living organisms.
What differences can be found within molecules?
Tiny charge differences
What are covalent molecules with dipoles known as?
Polar molecules
What are polar molecules held together by?
Electrostatic forces - they are weaker than ionic bonds but because they form between all the molecules in a substance there are a lot of them and they can have a major effect.
What is the best known example of an electrostatic force?
Hydrogen bonds.
When do hydrogen bonds occur?
When hydrogen atoms are covalently bonded to extremely electronegative atoms such as oxygen, nitrogen or fluorine. e.g when oxygenated hydrogen are covalently bonded to form a hydroxyl group, the oxygen always has a greater share of electrons than the hydrogen so the molecules have some polar nature.
What type of compound often contain hydroxyl groups giving them a polar nature?
Organic compounds.
2.1.3 Basic Biochemistry
What are organic molecules?
Organic molecules are compounds of carbon.
Compounds which are involved in human biochemistry normally contain what?
Mainly carbon, hydrogen and oxygen and are often large complex molecules.
What are inorganic compounds?
They do not contain carbon (there are exception such as carbonate ions or carbon dioxide) and they are usually small (made up of just a few atoms).
What are some important inorganic compounds in the body?
Water, salts including sodium chloride, and cerium acids and soluble bases (called alkalis)
What percentage of your body is water?
Between 50-70%
Water is an excellent solvent, what does this mean?
Many other compounds dissolve in it. Most of the bodies chemical reactions take place in solution in water.
Does water have a high or low heat capacity?
High heat capacity, meaning it takes a lot of energy to warm it up and a long time to cool down.
Water cannot be compressed, therefore what function can it provide in the body?
It acts as a protective cushion for vital body organs, for example water makes up an important part of the cerebrospinal fluid that cushions the brain and the amniotic fluid that protects the foetus in the amniotic sac.
What are salts, acids and bases called which dissolve in water?
Electrolytes
What happens to electrolytes when they dissolve in water?
Electrolytes dissociate when they dissolve in water so that their constituent positively and negatively changes particles called ins are able to move about in solution.
Can electrolyte in solution conduct electricity?
Yes
Salts, acids and bases are important features of body chemistry, what are examples of salts in living organisms?
Sodium and potassium ions from sodium and potassium salts are essential for the conduction of nerve impulses. Nitrate ions are needed for the production of proteins by plants.
Salts, acids and bases are important features of body chemistry, what do acids do in living organisms?
Acids transfer hydrogen ions (protons) to water molecules when they are dissolved in water so they are known as proton donors.
What is a base?
A substance which contains an ion or molecules which can take up hydrogen ions, they are proton acceptors. If a base is dissolved in water it takes some hydrogen ions from the water molecules and leaves hydroxide ions in the solution OH- ions.
What are bases which dissolve in water called?
Alkalis
What is the pH of an aqueous solution?
The pH of an aqueous solution is a measure of the concentration of the hydrogen ions in the solution.
If a solution has the same concentration of hydrogen ions and hydroxide ions what is it? what is its pH
Neutral, pH 7
If a solution has a pH below 7, what is it?
Acidic, it has more hydrogen ions than hydroxide ions
If a solution has a pH above 7, what is it?
Alkaline, it has more hydroxide ions than hydrogen ions in it.
Different fluids in the body have different pHs: What is the pH of the following:
Blood, Cerebro-spinal fluid, Pancreatic juice, Bile, Saliva, Urine and Vaginal Fluid
Blood = 7.35 - 7.45 Cerebro Spinal Fluid = 7.4 Pancreatic Juice = 7.1 - 8.2 Bile = 7.6 - 8.6 Saliva = 6.35 - 6.85 Urine = 4.6 - 8.0 Vaginal Fluid = 3.5 - 4.5
2.1.3.1 Carbohydrates:
What do carbohydrates include?
Sugars, starches, glycogen and cellulose.
What is the most common carbohydrate
The simple sugar called glucose?
What is the structure of glucose?
Glucose contains 6 carbon atoms joined together.
What are glucose molecules used in, in the body?
Glucose molecules are then in by the cell of your body and used cellular respiration to provide the energy needed for all the reactions that take place in your cells.
What are complex carbohydrates made up of?
Complex carbohydrates are made up of long chains of sugar molecules.
Name some examples of complex carbohydrates?
Glycogen is a complex carbohydrate stored in the muscles and the brain.
starch if important in our diets because it is uneasily digested complex carbohydrate.
Cellulose is a very important complex carbohydrate that makes up the cell walls of plants - we cannot digest cellulose so it plays an important role as fibre in our digestive system
What percentage of our body mass is carbohydrate?
the body cannot store much carbohydrate, it makes up up 2-3% of your body mass.
What percent of organic matter in the body do proteins account for?
Over 50%
What are the building blocks of proteins called?
Amino acids.
Joining together amino acids into long chains forms what?
Peptides
What associates to form proteins?
Peptide chains.
What are protein molecules often folded into?
Complex 3D shapes which are important for the way they function.
What is important for holding together the 3D shapes of the protein molecules?
Hydrogen Bonds.
A healthy adult body consists of what percentage of protein?
About 12-18%
Proteins that are involved in chemical reactions, enzymes or which bind to receptors such as hormones and antibodies are known as what?
Functional proteins
Proteins which form the bulk of many tissues are known as what?
Structural Proteins, for examples action and myosin in muscle or keratin in the skin.
2.1.3.3 Lipids:
What percentage of the body mass do lipids make up?
Lipids are organic compounds and mae up 18-25% or more of the body masss?
Lipids are hydrophobic, what does this mean?
They do not dissolve in water or watery solutions.
What are triglycerides made up of?
Triglycerides are made up of 3 fatty acids joined to a molecule of glycerol. The type of lipid is determined on the combination of fatty acids.
What are triglycerides good stores of in the body?
Triglycerides are highly concentrated energy stores for the body. The provide more then twice as much energy per gram as carbs or proteins.
What are phospholipids?
Phospholipids are triglycerides where one of the fatty acids is replaced by a phosphate group - this results in a polar molecules, important role in the cell membranes.
What are steroids?
Steroids are another type of lipid here the molecules for a ring structure.
What important functions do steroid hormones have in the body?
Steroid hormones are very important in controlling the body responses to stress, sexual development and in reproduction.
What is an important steroid?
Cholesterol, which is manufactured by the liver and also found in animal products such as meat, cheese and eggs. Cholesterol is vital for brain functioning and the production of many hormones.
What are the information molecules of the cell?
Nucleic acids - they carry information needed to form new cells.
The information is carried in the form of a code molecule of what?
DNA deoxyribonucleic acid
What is another nucleic acid which is used to carry the DNA code into the body of the cell and use it to make proteins?
RNA ribonucleic acid
DNA and RNA are both large polymers made up of long chains of nucleotides, what is each nucleotide made up of?
A sugar, a nitrogen-containing base and phosphoric acid. the arrangement of the nucleotides determines the structure of the molecule.
What shape do the long strands of DNA form?
They are coiled into a double helix.
2.1.4 Enzymes:
What are enzymes?
Enzymes are proteins that act as biological catalysts, speeding up chemical reactions by lowering the activation energy without being affected themselves.
What determines an enzymes active site?
The tertiary or quaternary £D structure of a proteins
What is the active site?
The active site its an area of the enzyme that binds to a specific molecule or type of molecule (the substrate) to catalyse a reaction.
What happens when a substrate(s) binds to the active site?
The binding of the substrate or substrates to the active site of the enzyme lowers the activation energy so the reaction takes place more easily.