Unit 2-metabolism and survival Flashcards
(94 cards)
1
Q
What is a metabolic pathway
A
An integrated series of enzyme controlled reactions
2
Q
anabolic reaction
A
Build up large molecules from small molecules
Requires energy
3
Q
Catabolic reactions
A
Break down large molecules into smaller molecules
releases energy
Cats destroy things
4
Q
what cell organelle have membranes
A
- mitochondria
- chloropplast
Higher surface to volume ratio allowing high concentrations of subtrates inside.
lleading to high reaction rates
5
Q
Membrane pores
A
Allows diffusion of specific molecules across membrane
6
Q
membrane pumps
A
transports molecules against concentration gradient
7
Q
Membrane enzyme
A
speed up the rate of bio chemical reactions in the cell
8
Q
How ar metabolic pathways controlled
A
By the presence of absence of particular enzymes and the regulation of the rate of reactions of key enzynes
9
Q
activation energy
A
- The energy required to initiate a chemical reaction
- enzymes lower the acitivation energy required for reactions to take place
10
Q
Affinity
A
- The tendency of a molecule to bind to an enzyme
- Substarate molecules have high affinity for th activ site of an enzyme [bind willingly]
- products of enzyme reactions have low affinity for the active site allowing them to leave the acive site
11
Q
induced fit
A
- The active site is not rigid structure it is flexible
- when the substarte enters the active site, the enzyme and the active site chnage slightly to make the active site fit closly round the substrate molecule
12
Q
enzyme inhibition
A
An inhibitor is a substance which reduces the rate of enzyme controllled reaction
2 main types: Competative
non competative
13
Q
Competative inhibators
A
- competativeinhibators bind at the active site of an enzyme preventing substrate to bind
- competative inhibators can be reversed by increasing substrate cincentration
14
Q
Non competative inhibators
A
- Non competative inhibators bind to another part of the enzyme, changing the shap if the active site preventing the substrate from binding
- Non competative inhibators cannot be reversed
15
Q
ATP & ADP
A
- Energy is released froma molecules of ATP when the last bond brakes forming ADP
- ATP can be broken down to release energy or can can be made which requires energy
adenosine tri phosphate and adenosine di phospahte
16
Q
Feedback inhibators
A
- Feed back inhibators occur when the end product in a metabolic pathway reaches a critical concentration
- The end product then inhibits an earlier enzyme, blocking the pathway therfore preventing further synthesis of the end product
17
Q
Mitochondria
A
Matrix-bit inside squigaly bit
Mitochondria matrix-folded to allow large surface area therfore faster rate of reaction
18
Q
Glycolysis
A
- Glycolysis is the breakdown of glucose to pyruvate in the cytoplasm.
- ATP is required for the phosphorylation of glucose and intermediates during the energy investment phase of glycolysis.
- This leads to the generation of more ATP during theenergy pay-off stage and results in a net gain of ATP.
- Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the coenzyme NAD, forming NADH.
19
Q
Phosphorylstion
A
- addition of phosphate
- ATP is broken down to ATD+pi
- The released phosphate can phosphorylate other molecules
20
Q
What happens to pyruvate in the presence of oxygen
A
In aerobic conditions, pyruvate is broken down to an acetyl group that combines with coenzyme A forming acetyl coenzyme A.
21
Q
v
Citric acid cycle
A
- In the citric acid cycle the acetyl group from acetyl coenzyme A combines with oxaloacetateto form citrate.
- During a series of enzyme controlled steps, citrate is gradually converted
back into oxaloacetate which results in the generation of ATP and release of carbon dioxide. - The citric acid cycle occurs in the matrix of the mitochondria
- Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the coenzyme NAD, forming NADH.
22
Q
ATP synthase
A
- In the inner mitochondia membrane
- an enzyme
- The flow of hydrogen ions back through the membrane protein ATP synthase results in the production of ATP
23
Q
Electron transport chain
A
- ATP synthesis — electrons are passed along the electron transport chain releasing energy.
- This energy allows hydrogen ions to be pumped across the inner mitochondrial membrane.
- The flow of these ions back through the membrane protein ATP synthase results in the production of ATP.
- Finally, hydrogen ions and electrons combine with oxygen to form water.
24
Q
Fermentation in aniaml cells
A
- In the absence of oxygen, fermentation takes place in the cytoplasm.
- **In animal cells, pyruvate is converted to lactate in a reversible reaction. **
- Fermentation results in much less ATP being produced than in aerobic respiration.
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Fermentation in plant cells
* In the absence of oxygen, fermentation takes place in the cytoplasm.
* **In plants and yeast, ethanol and CO2 are produced in an irreversible reaction. **
* Fermentation results in much less ATP being produced than in aerobic respiration.
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How can metabolic rate be measured
* Oxygen consumption-Oxygen probe
* Carbon dioxide Production-Oxygen probes,respirometers
* Heat production-Calorimeters
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How can metabolic rate be measured
* Oxygen conumption-Oxygen probes
* Carbon dioxide prodution-Carbon dioxide porbes, respirometer
* Heat production calorimeters
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Organism with High metabolic rate
* Organisms with high metabolic rates require more efficient delivery of oxygen to cells.
* Birds and Mammals have higher metabolic rates than Reptiles and Amphibians, which in turn have higher metabolic rates than Fish.
(Birds & Mammals > Reptiles & Amphibians > Fish)
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Circulatory system of Birds and mamalls
* Birds & Mammals have a **Complete Double** circulatory system consisting of **2 Atria & 2 ventricals**. **4** chambers
* Complete Double circulatory systems enable **higher metabolic rates to be maintained**. There is **no mixing of oxygenated & deoxygenated blood** and the oxygenated blood can be pumped out at a **higher pressure**. This enables more **efficient** Oxygen delivery to cells.
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Circulatory system of amphibians and reptiles
* Amphibians & most reptiles have an **Incomplete Double** circulatory system consisting of **2 Atria & 1 Ventricle. 3 chambers**
* Incomplete Double circulatory systems are** less efficient** in the delivery of oxygen to cells since there **is mixing of oxygenated and deoxygenated blood** in the **single ventricle** present.
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Circulatory system of Fish
* Fish have a **single circulatory system** consisting of **1 Atrium & 1 Ventricle**. **2 chambers**.
*
* It is called a single circulatory system because the **blood only passes through the heart** **ONCE** in each complete circuit around the body.
* As blood passes through a capillary bed ( e.g. at the gills), there is **drop in blood pressure**. This means that **blood is delivered** to the capillary bed in the body tissues at** LOW PRESSURE.**
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Affect of abiotic factors on metbabolic rate
* The ability of an organism to maintain it’s metabolic rate is affected by external abiotic factors.
Abiotic factors which affect an organisms ability to maintain metabolic rate include:
* Temperature
* Salinity [saltyness of water]
* pH
36
Conformers
| Reptiles [cold blooded]
* A Conformers **internal environment** is **dependant** upon it’s **external environment.**
* Conformers use** Behavioural** responses to **maintain optimum** metabolic rate. E.g. Lizards can maintain their body temperature by basking in the sunshine.
* Behavioural responses by conformers allow them to tolerate variation in their external environment to **maintain optimum metabolic rate.
**
* Conformers have **LOW METABOLIC COSTS** and a **NARROW RANGE OF ECOLOGICAL NICHES.**
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Regulators
| Mammals [humans]
* A Regulator can **maintain** it’s internal environment **regardless** of it’s **external environment.**
* Regulators use** metabolism to control their internal environment**, which **INCREASES THE RANGE OF POSSIBLE ECOLOGICAL NICHES.**
* This regulation requires **ENERGY** to achieve HOMEOSTASIS. This **INCREASES THEIR METABOLIC COSTS.**
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Factors affect an organisms ability to maintain metabolic
*** The ability of an organism to maintain its metabolic rate is affected by external abiotic factors.**:
-Temperture
-Salinity
-pH
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Control mechanism by which Regulators maintain Homeostasis
NEGATIVE
FEEDBACK CONTROL.
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# Thermoregulation
Temperature monitoring centre in the brain
**Hypothalamas**
* Information is communicated by **electrical impulses through nerves** to the effectors, which bring about corrective responses to return temperature to normal.
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Response to an Increase in Body Temperature
* Sweating
* Vasodilation of Blood Vessels
* Decreased metabolic rate
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# Too hot
Sweating
* body heat is used to evaporate water in the sweat, cooling the skin.
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# Too hot
Vasodilation of Blood Vessels
* Dilation of blood vessels
* Increases blood flow to the skin (reason why we look red when hot)
* Allows heat to be lost by radiation from the skin surface.
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Response to a Decrease in Body Temperature
* Shivering
* Vasoconstriction of Blood vessels
* Hair erector muscles contracting
* Increased metabolic rate
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# Too cold
Shivering
Muscle contraction generates heat to return body temperature to normal
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# Too cold
Vasoconstriction of Blood vessels
Decreased blood flow to the skin (reason why we look pale when cold) decreases heat loss from the skin surface.
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# Too cold
Hair Erector muscles contract
Hair erector muscle contracts trapping a layer of insulating air
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Increased metabolic rate
More heat is produced to return body temperature to
normal
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Importance of thermo regulation
Thermoregulation ( control of internal body temperature to within tolerable limits) is
**essential for optimal enzyme activity and high diffusion rates to maintain metabolism.**
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Why do aniamls use dormancy to survive adverse conditions
Allow survival during a period when the costs of continued normal metabolic activity would be too high.
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What happens to the body during dormency
During dormancy there is a decrease in **metabolic rate, heart rate, breathing rate and body temperature.**
To save energy
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Predictive Dormancy
**occurs before the onset of adverse conditions.**
This is common inenvironments which have predictable seasons where the temperature and number of hours of daylight can be used as triggers.
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Consequential Dormancy
* **occurs after the onset of adverse conditions**
* common among organisms living in unpredictable environments.
* Advantage-organism may remain active for longer and continue to make use of
* the available resources.
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# Types of dormancy
Hibernation
Some mammals survive during **Winter/Low temperatures** by
hibernating.
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# Types of dormancy
Aestivation
This allows survival in periods of** High temperature or Drought.**
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# Types of dormancy
Dily torpor
This is a period of reduced activity in some animals with high metabolic rates ( e.g. small birds & mammals)
Nearly coma
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Migration
* **Avoiding adverse condtions**
* Migration **avoids metabolic adversity** by expending energy to **relocate** to a more suitable environment.
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Innate migration
Migrations behaviour is **inherited **
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Learned migration
Migration behaviour gained by experience
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Ways to track migrations
* satailite tracking
* Leg rings
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What do micro orginisms include
* Archaea
* Bacteria
* Some species of Eukaryotes (e.g. yeast & protozoans)
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How do micro orginism produce a wide varity of product
Micro-organisms use a **wide-variety of substrates** for metabolism and produce a** range of products** from their metabolic pathways.
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Why are microrginisms used
Micro-organisms are used because of their **adaptability, ease of cultivation** (growing) and** speed of growth.**
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What do microrginsims require for growth
When culturing micro-organisms, their growth media requires **raw materials for biosynthesis** as well as an **energy source.**
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Where does the nergy source come from when culturing
An energy source is derived either from **chemical substrates** such as **carbohydrates** or from **light** in the case of photosynthetic micro-organisms.
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# STOP
Culture conditions
* **Sterility** - sterile conditions in fermenters reduce competition with desired microorganisms for nutrients and reduce the risk of spoilage of the product.
* **Temperture** - Temperature must be controlled
* **Oxygen** - Oxygen levels may be controlled by aeration (air pump).
* **pH** - pH can be regulated by adding pH Buffers or the addition of acid or alkali.
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Phases of Growth
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Culture growth phases
* Lag - During the Lag phases **ENZYMES ARE INDUCED** to metabolise substrates.
* Log/Exponential - This phase contains the **most rapid growth** of micro-organisms due to **plentiful supply of nutrients.**
* Stationary - This phase occurs due to the nutrients in the culture media becoming **depleted** and the production of toxic metabolites. Secondary metabolites, such as **antibiotics**, are also produced. In the wild these metabolites confer an ecological advantage by allowing the micro-organisms which produce them to outcompete other micro-organisms.
* Death - This phase occurs due to the **toxic accumulation of metabolites** or the **lack of nutrients** in the culture.
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How can wild strains of microorginsim be improved
Wild strains of micro-organisms can be improved by **Mutagenesis** or **Recombinant DNA technology.**
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Mutagenesis
* Mutagenesis is the **creations of mutations**
* Mutagenesis is the process of **inducing mutations**.
* Exposure to **UV** light and other forms of **Radiation** ( e.g. X-rays or Gamma rays) or **Chemicals** ( e.g Mustard gas) results in mutations.
* Some of these mutations produce an improved strain of micro-organism.
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Term
Definition
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Mutagenesis
The process of inducing mutations in an organism's DNA
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Improved strain
A strain of micro-organism that has been modified to have desirable properties
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Recombinant DNA technology
The use of recombinant plasmids and artificial chromosomes to transfer foreign DNA into a host cell
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Vector
A DNA molecule used to carry foreign genetic information from a donor organism into a host cell
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Host cell
A cell that takes up a recombinant plasmid
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Mutation
A change in the DNA sequence
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Plasmid
A small, circular piece of DNA that is found in bacteria
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Restriction enzyme
An enzyme that cuts DNA at a specific sequence
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What are restriction endonucleases?
Restriction endonucleases are enzymes that cut DNA at specific sequences.
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How are restriction endonucleases used in recombinant DNA technology?
Restriction endonucleases are used to cut open plasmids and specific genes out of chromosomes
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How are sticky ends used in recombinant DNA technology?
Sticky ends can base-pair with each other
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How is ligase used in recombinant DNA technology?
Ligase is used to join the sticky ends of a plasmid and a gene together
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What are restriction sites?
Restriction sites are specific sequences of DNA that are recognized and cut by restriction enzymes.
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What is an origin of replication?
An origin of replication is a sequence of DNA that tells the cell where to start copying the DNA.
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What is a selectable marker?
A selectable marker is a gene that allows scientists to identify cells that have been transformed with a plasmid.
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What are safety precautions for recombinant DNA technology?
Safety precautions for recombinant DNA technology include using genes that prevent the survival of the micro-organism in an external environment.
Antibiotics
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What are the limitations of using prokaryotes in recombinant DNA technology?
One limitation of using prokaryotes in recombinant DNA technology is that they may not be able to correctly fold proteins from eukaryotic DNA. This is because prokaryotes do not have the same post-translational modification machinery as eukaryotes.
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What are recombinant yeast cells?
Recombinant yeast cells are yeast cells that have been genetically modified to produce a specific protein.
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How are recombinant yeast cells used in recombinant DNA technology?
Recombinant yeast cells can be used to produce active forms of proteins that are inactive in bacteria. This is because yeast cells are eukaryotes
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What happens during the lag phase of microbial growth?
During the Lag phases ENZYMES ARE INDUCED to metabolise substrates.
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What characterizes the log/exponential phase of microbial growth?
The log/exponential phase contains the most rapid growth of microorganisms due to a plentiful supply of nutrients.
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What occurs during the stationary phase of microbial growth?
The stationary phase occurs due to depletion of nutrients and the production of toxic metabolites. Secondary metabolites, such as antibiotics, are produced, which provide an ecological advantage to microorganisms in the wild.
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What happens during the death phase of microbial growth?
The death phase occurs due to the toxic accumulation of metabolites or the lack of nutrients in the culture.
