Biology Chp. 5
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- What is the 1st Law of Thermodynamics?
- any isolated system has a finite amt. of energy that cannot be added to or lost
- What is the 2nd Law of Thermodynamics?
- the entropy (disorder) of the universe is ever-increasing
- Compare exergonic and endergonic reactions & give an example of each.
- Exergonic reactions show a net ENERGY RELEASE, while endergonic reactions require ENERGY INPUT. Ex. of EXERgonic: aerobic respiration Ex. of ENDERgonic: photosynthetic reactions
- What is the change of ADP to ATP called and why?
- Phosphate-group transfers are known as phosphorylations.
- Define reactant
- starting substance in any metabolic reaction
- Define intermediate
- substance formed during a reaction sequence
- What are cofactors and what do they do?
- metal ions & coenzymes that move funct. groups, atoms, and electrons. Ex. NAD+
- What is chemical equilibrium?
- reaction rate is about the same in both directions
- What is a redox reaction?
- electron transfers that cells use to gain energy
- What happens to a molecule when it is oxidized? Reduced?
- One molecule gives up electrons (is oxidized) and another is reduced when it gains them.
- What is a metabolic pathway?
- enzyme-mediated sequences of reactions
- What are the 2 types of metabolic pathways? Give ex.
- 1. Biosynthetic/anabolic: req. energy inputs ex. assembly of glucose, starch, proteins 2. Degradative/catabolic: exergonic, can break down molecules to smaller, lower energy products ~ ex. aerobic respiration
- When chemical bonds are broken in a reaction, ____ is released or absorbed.
- energy
- What is a catalyst?
- Substance that speeds up a chemical reaction
- True/Fale: Enzymes are proteins
- True
- A biological catalyst is an ___.
- enzyme
- the substance that an enzyme works on is called the ____
- substrate
- Complete. Enzyme ~ Substrate lactase ~ ____ maltase ~ ____ protease ~ ____ lipase ~ ____
- lactose maltose protein lipids
- most enzymes end in -__
- -ase
- where do the substrate bind to the enzyme?
- on the active site
- the active site and the enzyme have ____ shapes
- complementary
- The Lock and Key Model compares the ____ to a key and the ____ to a lock.
- enzyme to a key substrate to a lock
- What does the Lock and Key model tell you about enzymes?
- ~ specific b/c of their shape ~ can be reused ~ specific for one substrate
- What does the Induced Fit model state?
- ~ the enzyme and the substrate may not fit perfectly ~ the strain on the molecules may speed up the reaction
- What factors affect an enzymes ability to work? What happens to the enzymes?
- ~ pH ~ temperature They get denatured (change shape)
- What are coenzymes?
- class of organic compounds (more complicated than cofactors), can be modified during reactions
- Are polar molecules attracted to or not attracted to water?
- polar molecules are attracted to water
- which substances can easily pass through cell membranes? Give 4 ex
- oxygen, carbon dioxide, small molecules, nonpolar molecules, water
- which substances cannot easily pass through the membrane? 4 ex
- large molecules, polar molecules, glucose, and ions
- How can molecules that do not easily pass through the lipid bilayer get through the membrane?
- - with the help of proteins
- diffusion ~ the random movement of molecules from ___ to ___ concentration
- high to low
- diffusion is a type of (passive/active) transport
- passive
- Name 3 factors that affect the rate of diffusion
- 1. temp. 2. size of molecule 3. pressure 4. steepness of concentration gradient
- the concentration of water is influenced by concentration of ___
- solutes
- Define hypertonic, hypotonic, and isotonic
- hypertonic = higher solution outside the cell hypotonic = lower solution outside the cell isotonic = equal
- What is facilitated diffusion? What substance is necessary for it to happen?
- diffusion with the help of proteins ~ glucose is needed to help move protein through channels
- What are the two types of endo and exocytosis?
- 1. phagocytosis - large solid 2. pinocytosis - liquid droplet
- What happens in endocytosis?
- cell brings molecule into itself using vacuoles
- What happens in exocytosis?
- vessicle moves toward c.m., fuses w/ cell membrane, bursts & releases contents
- Where does the energy to change ADP to ATP come from?
- glucose
- What is the cause of diffusion and osmosis?
- the concentration gradient
- What substances regulate metabolic pathways? Give some examples of metabolic pathways.
- enzymes & cofactors regulate them ex. photosynthesis, cellular respiration
- How are substances moved thru membranes against the concentration gradient?
- Active transport using ATP and protein pumps
- What substances move by simple diffusion? Which move by facilitated diffusion?
- simple: oxygen, carbon dioxide facilitated: glucose
- Explain how a molecule can "carry" energy
- ATP ~ bonds between phosphates