MB S1 Flashcards
What are enzymes?
Enzymes are proteins, that have amino acids as their building blocks.
What are the main elements that make up the amino acids in the proteins?
Carbon, Nitrogen, Oxygen and Hydrogen
What is the role of enzymes?
They control the rate of chemical reactions in the body. They usually speed up reactions.
What is a catalyst?
A catalyst is a substance that speeds up a chemical reaction.
How is a catalyst and enzyme similar?
Enzymes are organic catalysts, as they also speed up reactions within the body.
What is specific about a catalyst when involved in a reaction?
Whilst the catalyst speeds up the reaction, they do not become apart of the reaction. And therefore can be reused over and over again (so can enzymes)
How is an enzyme held together?
The enzyme is held into a specific shape with weak hydrogen bonds.
Are enzymes specific to their uses?
Yes, there are specific enzymes for different chemical reactions around the body.
What type of Catalyst is a enzyme?
An Organic Catalyst
What does an enzyme do?
Speed up chemical reactions.
What model best describes the functions of an enzyme?
A lock and Key model
How does a enzyme help the speed of a chemical reaction?
It lowers the activation energy.
What is the active site?
The active site is the small part of an enzyme where the substrate molecules bind and undergo a chemical reaction.
How does this chemical reaction occur on the active site?
The substrate collides with the active site of the enzyme… where the chemical reaction then occurs. Acting as a organic catalyst.
Enzymes are made of…
…proteins (chains of amino acids) which are held together by weak hydrogen bonds.
heat and acids can break the hydrogen bonds… which then change?
The shape of the enzyme
What can heat and acids do to the weak hydrogen bonds in an enzyme?
They break them, which then change the specific shape of the enzyme.
When an enzyme is broken with heat or an acid, it changes the nature of the enzyme. What is the term that explains this?
The enzyme is “denatured”
What is metabolism?
The sum total of all the chemical reactions that occur in an organism in order to maintain life.
What is the role of an enzyme in terms of acting as an organic catalyst?
Enzymes are organic catalysts. A catalyst is a general term for any substance that speeds up or brings about a chemical change, without itself being used up.
What do enzymes control?
All the chemical processes within living systems. Enzymes are produced within living cells.
What is the chemical composition of an enzyme?
Enzymes are proteins. They are made up of amino acids that are linked and then folded to produce a 3-D structure. The folded shape is related to enzyme specificity.
Each enzyme catalyses a…
distinct chemical reaction.
There are two models which identify the Specificity of the enzymes, these are known as?
The lock and key model and also the induced-fit Model
Whats the Lock and Key Model?
A lock and key model for enzyme specificity shows that a certain enzyme can only react with a certain substrate because of the shape of its active site which correlates to the shape of the substrate. Neither chemical will change to fit the other.
Whats the Induced-Fit Model?
The shape of the active site and the substrate molecules will both modify slightly, so the enzyme can react with more substrates. These enzymes have a lower specificity.
What is pH?
The pH is a way of describing the acidity of a substance. A pH of 7 is neutral, which means it is neither acidic nor alkaline. High acidity is shown by a lower pH.
How are enzymes related to pH?
Enzymes have an optimum pH for activity, for example digestive enzymes in the stomach work best under conditions below pH 6. Changing pH reduces an enzyme’s activity.
Why is the maintenance of a constant internal environment important for optimal metabolic efficiency?
- Enzymes control all metabolic processes in the body.
- Enzymes work optimally in an environment where their optimum temperature and pH conditions are met. At temperatures and pH values other than the optimum, the enzymes fail to work efficiently and kept as stable as possible.
- If internal temperatures were to rise too much, enzymes would denature (breakdown).
- If internal temperatures drop, enzymes cannot function.
What is homeostasis?
Homeostasis is the process by which the internal environment is kept within normal limits, regardless of the external environmental conditions
What conditions does homeostasis include?
temperature, pH, gas levels, water and salt concentrations
What do the conditions of homeostasis allow?
This allows the enzyme’s optimal conditions to be met and the body to work efficiently and be kept as stable as possible.
Homeostasis consists of two stages, what are they?
- Detecting changes from the stable state
2. Counteracting changes from the stable state
During the step of “Detecting changes from the stable state” in homeostasis, what does this include?
A receptor detects a change in some variable in the organism’s internal environment, for example, sensory neurons in the skin pick up a decrease or increase in temperature of air surrounding the body.
During the step of “Counteracting changes from the stable state” in homeostasis, what does this include?
An appropriate response occurs that counteracts the changes and thus maintains the stable environment, for example, shivering to generate heat in muscles
What is the role of the nervous system in detecting and responding to environmental changes?
The nervous system sends messages to the brain & back to the sensory organs.
In the nervous system, the brain, nerves and sense organs all play apart in detecting and responding to environmental changes. what is it for the brain, nerves and sensory organs?
Brain = Processing Information
Nerves = Sending Information
Sense Organs = Detecting Information
There is a broad range of temperatures that has life found within it, what is the narrow limits of general life?
-70 degrees C > 200 degrees C
In the range of temperatures found for life, what is the temperature range for Hyperthermophiles?
-70 degrees C > 0 degrees C
In the range of temperatures found for life, what is the temperature range for most organisms and mammals?
0 degrees C > 50 degrees C
In the range of temperatures found for life, what is the temperature range for Extremophiles?
100 degrees C > 200 degrees C
Whats an ectotherm?
An animal that is dependent on external sources of body heat.
Whats an endotherm?
An animal that is dependent on or capable of the internal generation of heat.
The Australian Diamond python is an ectotherm, or an endotherm?
Ectotherm
What is a physiological adaption?
The way an organisms body functions
What is a behavioral adaption?
The way an organism acts
What is a structural adaption?
It is the physical characteristics of an organism
What is a physiological adaption of a Australian Diamond Python in a cold condition?
Lies on eggs and shivers to create more heat within the body.
What is a structural adaption of a Australian Diamond Python in a cold condition?
Dark in color to absorb heat, and can therefore tolerate colder temperatures than most snakes.
What is a behavioral adaption of a Australian Diamond Python in a cold condition?
Basks in sun to raise body temperature.
Hibernation in winter.
Migration to warmer areas.
What is a behavioral adaption of a Australian Diamond Python in a warm condition?
Nocturnal- Hunting at night.
Burrowing during the day.
Is the Australian Red Kangaroo and Endotherm or an Ectotherm?
Endotherm
What is a physiological adaption of the Australian Red Kangaroo in a cold condition?
Increased metabolic rate to create more heat within the body.
What is a structural adaption of the Australian Red Kangaroo in a warm condition?
Panting to release heat.
Exposed areas of skin on the forelegs to increase evaporative cooling of blood for the area.
Shunting of blood from tail to exposed areas of skin to increase heat loss.
What is a behavioral adaption of the Australian Red Kangaroo in a cold condition?
Basking in the sun.
What is a physiological adaption of the Australian Red Kangaroo in a warm condition?
Decrease in metabolic rate.
What is a behavioral adaption of the Australian Red Kangaroo in a warm condition?
Nocturnal.
Licking forearms to increase evaporation from the skin.
Sitting in the shade.
What are some responses made by plants due to temperature change?
Leaf Fall, Radiation, Heat-shock proteins, Transpiration, Die Back, Orientation of Leaves, Seed Dispersal and Vernalisation
In a plants response to temperature change what is Leaf fall?
Plants reduce their surface area exposed to heat by dropping their leaves.
This also reduces the amount of water that is lost through transpiration.
In a plants response to temperature change what is Radiation?
Some plants living in very exposed areas, such as sand dunes, reduce the amount of heat absorbed by having shiny leaves that reflect solar radiation.
In a plants response to temperature change what Heat Shock proteins?
These are proteins produced by plants that are under stress from very high temperatures. These molecules are thought to stop enzymes denaturing, so normal cell reactions can continue.
In a plants response to temperature change what is Transpiration?
The movement of water up the plant from the roots to the leaves via the transpiration system serves to cool the plant during hot conditions.
The evaporation of the water from the stomata of the leaves also serve to cool the plant.
In a plants response to temperature change what is Die Back?
In harsh conditions the shoots and leaves of a plant may die, but left in the soil are bulbs, roots or rhizoids that will begin to grow again when favourable conditions return.
In a plants response to temperature change what is Orientation of Leaves?
Vertical orientation of some leaves has the advantage of reducing the amount of leaf surface area in contact with sun rays, e.g. Eucalyptus leaves hang vertically.
In a plants response to temperature change what is Seed Dispersal?
Some Australian natives require extremely high temperatures, such as those produced by a fire, to germinate their seeds.
Plant seeds from species such as Banksia ericifolia are only able to open their seed coats when they are exposed to fire.
In a plants response to temperature change what is Vernalisation?
This is when plants must be exposed to cold conditions to produce flowers and therefore reproduce. Plants in alpine regions use vernalisation to reproduce when conditions are more favourable at the end of winter.
The presence of cold conditions will stimulate flowers to grow, and when spring approaches they are almost mature.
Whats another name for an organic catalyst?
Enzyme
The special molecules that control the chemistry of each cell are?
Enzymes
Metabolism is chemistry that is controlled by?
Enzymes
Everything that happens inside a living thing is a matter of cell chemistry. which is?
metabolism