Exam (elaborations)
BIL 255 CHAPTER 13 REVIEW EXAM QUESTIONS AND ANSWERS
- Course
- Institution
BIL 255 CHAPTER 13 REVIEW EXAM QUESTIONS AND ANSWERS...
[Show more]
Content preview
cells require - ANSWER a constant supply of energy to generate and maintainthe biological order that allows them to grow, divide, and carry out their day-to-
day activities
energy comes from - ANSWER chemical bond energy in food molecules,
which thereby serve as fuel for cells
most important fuel molecules - ANSWER sugars
plants and animals
sugar - ANSWER Plants make their own sugars from CO2 by photosynthesis
Animals obtain sugars - and other organic molecules that can be chemically
transformed into sugars - by eating plants and other organisms
breakdown of sugars in animals and plants - ANSWER the process whereby
all these sugars are broken down to generate energy is very similar in both
animals and plants
In both cases, the organism's cells harvest useful energy from the chemical bond
energy locked in sugars as the sugar molecule is broken down and oxidized to
carbon dioxide and water - a process called cell respiration
The energy released during these reactions is captured in the form of "high
energy" chemical bonds - covalent bonds that release large amounts of energy
when hydrolyzed - in activated carriers such as ATP and NADH
These carriers in turn serve as portable sources of chemical groups and electrons
needed for biosynthesis
high energy chemical bonds - ANSWER covalent bonds that release large
amounts of energy when hydrolyzed
,breakdown of glucose - ANSWER generates most of the energy produced in
the majority of animal cells
If a fuel molecule such as glucose were oxidized to CO2 and H2O in a single
step, ex by fire, it would release - ANSWER an amount of energy many times
larger than any carrier molecule could capture
enzymes and breakdown of sugar - ANSWER cells use enzymes to carry out
the oxidation of sugars in a tightly controlled series of reactions
Thanks to the action of enzymes - which operate at temperatures typical of
living things - cells degrade each glucose molecule step by step, paying out
energy in small packets to activated carriers by means of coupled reactions
In this way, much of the energy released by the breakdown of glucose is saved
in the high energy bonds of ATP and other activated carriers, which can then be
made available to do useful work for the cell
2 ways in which animals make ATP - ANSWER First, certain energetically
favorable enzyme catalyzed reactions involved in the breakdown of foods are
directly coupled to the energetically unfavorable reaction ADP + Pi = ATP
Thus the oxidation of food molecules can provide energy for the immediate
production of ATP
Most ATP synthesis however requires an intermediary
In this second pathway to making ATP, energy from other activated carriers is
used to drive ATP production
This process is called oxidative phosphorylation, takes place in the inner
mitochondrial membrane and is described in detail later
oxidative phosphorylation - ANSWER occurs in the inner mitochondrial
membrane
substrate level phosphorylation - ANSWER in the cytosol and mitochondrial
matrix
, produce both ATP and the additional activated carriers that will subsequently
help drive the production of much larger amounts of ATP by oxidative
phosphorylation
breakdown of molecules - ANSWER The proteins, fats and polysaccharides
that make up most of the food we eat must be broken down into smaller
molecules before our cells can use them - either as a source of energy or as
building blocks for making other organic molecules
catabolism - ANSWER process in which enzymes degrade complex organic
molecules into simpler ones
three stages
stage 1 of catabolism - ANSWER enzymes convert the large polymeric
molecules in food into simpler monomeric subunits: proteins into amino acids,
polysaccharides into sugars, and fats into fatty acids and glycerol
This stage, also called digestion, occurs either outside cells (in the intestine) or
in specialized organelles within cells called lysosomes
After digestion, the small organic molecules derived from food enter the cytosol
of a cell, where their gradual oxidative breakdown begins
stage 2 of catabolism - ANSWER a chain of reactions called glycolysis splits
each molecule of glucose into two smaller molecules of pyruvate
Sugars other than glucose can also be used, after first being converted into one
of the intermediates in this sugar splitting pathway
Glycolysis takes place in the cytosol and in addition to producing pyruvate, it
generates two types of activated carriers: ATP and NADH
The pyruvate is transported from the cytosol into the mitochondrion's large,
internal compartment called the matrix
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Boostertips. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
77254 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now