Week 1 Flashcards
Metabolic pathways, work in cells, energy, energy in metabolic pathways, ATP
What are the 3 types of work of cells?
Movement/mechanical, membrane transport and chemical synthesis
What is the name of the small organelles that are used to move things to specific locations in the cell?
Vesicles
What is the function of cytoplasmic streaming?
For big cells to mix things around for equal concentrations, such as organelles, nutrients and biomolecules
What are the names of the three motor proteins that power movement
Kinesin, Dynein, Myosin
What are the names of the cytoskeletal tracks and which motor proteins use them?
Microtubules, for Kinesin and Dynein; Microfilaments (or actin filaments) for Myosin
How do entire cells move (cell motility)?
Their actin cytoskeleton “pushes” the front end of the cell forward and also “pulls” the back of the cell forward
Why is membrane transport important?
For maintaining osmotic balance and for nutrient uptake, excretion of waste, nerve signalling and muscle contraction
Explain the function of the sodium pump (sodium/potassium ATPase) and which cells these are important for
The sodium pump maintains sodium and potassium at different concentrations across the cell membrane. It is particularly important in nerve cells and brain cells for nerve impulses
Explain the function of the calcium pump (calcium ATPase) and which cells these are important for
The calcium pump keeps the calcium levels in the cells low by moving it out. It is particularly important in muscle cells, which can respond to sudden increases in calcium and contract
Explain metabolic pathways
A series of chemical reactions that occur within a cell, that start with a substrate and finish with a product/reactant
How are metabolic reactions typically controlled?
By enzymes, which are usually specific. They catalyse reactions.
Explain metabolic disequilibrium and why its important
In cells the reactions don’t come to equilibrium - instead of the product being converted back to the reactant, it keeps going down the metabolic pathway by reactions. The free energy changes in these reactions allows cells to do work. If there was equilibrium and no free energy changes the cells would not be able to do work.
Explain catabolic pathways
Complex molecules are broken into simpler ones. This is spontaneous and releases energy.
Explain anabolic pathways
Complex molecules are built from simple ones. This is non-spontaneous and requires energy.
What are the three main ways that metabolism is regulated via enzymes?
Allosterically, covalently and genetically
Explain energy coupling
The energy released in catabolic pathways can be used for anabolic pathways. The energy released from catabolic pathways is converted into useful energy carriers such as ATP, NADH and NADPH
Explain metabolic regulation and why it is important
Cells are able to control their metabolism by regulating enzymes. This ensures that they have the materials and energy to do work and hence be alive.
What is the difference between kinetic and potential energy?
Kinetic energy relates to anything that moves, such as light, electrical or heat. Potential energy is related to structure or location such as chemical energy or proton gradient across a membrane
How is the free energy change of a glucose oxidation reaction (ΔG) calculated? Is this an exergonic or endergonic reaction and what does that mean?
By subtracting G(glucose) from G(carbon dioxide and water). This is an exergonic reaction meaning energy is released and it is spontaneous.
What is the difference between an exergonic and an endergonic reaction?
In exergonic reactions energy is released and it is spontaneous (indicated by negative ΔG value), whereas endergonic reactions require energy and they are non-spontaneous (indicated by positive ΔG value)
ATP (adenosine triphosphate) is a nucleotide composed of what?
Adenine base, ribose sugar and 3 phosphates
Explain ATP hydrolysis
The reaction of ATP and water yields inorganic phosphate (Pi) and ADP and releases energy
What is the main difference between ATP and ADP
ATP has 3 phosphates whereas ADP has 2 (diphosphate), and ADP is more stable than ATP
Is having higher free energy more stable or unstable? What does this mean in terms of the 2nd law of thermodynamics?
Higher free energy is more unstable. Due to the 2nd law of thermodynamics there is a tendency to move to a more stable state, i.e. a state of lower free energy.
Why can organisms be ordered yet still increase the disorder of the universe?
There is always energy released/lost to the universe as things like heat during reactions. Reactions are never perfect, including energy coupling.
Around how much ATP is made in your body per day?
About the same amount as your weight, for example someone who weighs 85kg would produce around 85kg of ATP per day.
How is ATP made?
An inorganic phosphate (Pi) is added to ADP
Can cells use heat energy to do work? Why/why not?
No they cannot use heat energy to do work. Heat energy makes things move around more, but because it is not specific it cannot be used for work
