Chapter 4 Flashcards
How many chemical reactions take place to keep the cell in homeostasis?
thousands
How often does energy need to be supplied for these chemical reactions and enzymes to control the rate at which these reactions take place.
constantly
what are some examples of chemical reactions
Cellular respiration, Protein synthesis, Cell Cycle, Mitosis, Meiosis, DNA replication
the set of chemical reactions that acquire, store, and release energy in cell
Cellular metabolism
where does the energy in cellular metabolism come from?
the chemical bonds of nutrient molecules from the diet
what are the two types of metabolic reactions
anabolic and catabolic
what do anabolic reactions do
build large molecules from small ones
what is an example of anabolic reactions?
dehydration synthesis
what do catabolic reactions do?
break down large molecules to small ones
what is an example of a catabolic reaction
hydrolysis
what are some examples of anabolic reactions by dehydration synthesis
1) The production of glycogen (polysaccharide)
2) The production of triglycerides
3) The production of proteins
4) The production of nucleic acids
WHat are some examples of catabolic reactions by hydrolysis
Examples of Catabolic reactions by hydrolysis
1) Breakdown of carbohydrates into monosaccharides (Digestion)
2) Breakdown of fats into glycerol and fatty acids.
3) Breakdown of proteins into amino acids.
4) Breakdown of nucleic acids into sugar, phosphoric acid, and purine/pyrimidine
Cells perform metabolic reactions that take _____ chemical changes that happen in a fast and orderly manner thanks to _____.
hundreds of; enzymes
Without enzymes, would cells stay in homeostasis?
no, without enzymes reactions in cells would not happen fast enough to keep a cell in homeostasis because body temperature is not high enough
Metabolic reactions need _____ to happen.
energy (ATP)
Enzymes are catalysts. Enzymes are proteins that work by _____.
lowering the activation energy and speed the rates of chemical reactions
Are enzymes consumed in their function to speed the rate of the reaction?
no
Does each enzyme acts on on one specific substrate or multiple?
one specific
How does an enzyme recognize its substrate?
by the enzymes conformation
When the substrate changes because enzyme acted, the reaction has taken place and a _____ is formed.
new product
Every cell contains _____ to help complete reactions
hundreds of ensymes
Are enzymatic reactions reversible
many are
What does the rade/speed of enzyme-controlled reactions depend on?
- # of enzymes and substratemolecules in the cell
- how many substrates an
individual enzyme can process
per second
How many substrates can an individual enzyme produce per second
some enzymes can only process a few but other enzymes can process thousands per second
factors that alter enzymes:
Most enzymes are _____ and they can be denatured by _____
proteins
exposure to hear
radiation
electricity
fluids with extreme pH values
certain chemicals
what temp do enzymes become inactive
many at 45, nearly all denatured at 55
Some enzymes are inactive until they _____
combine with a cofactor or coenzyme
What is a sequence of enzyme-controlled reactions
metabolic pathway
What controls the entire rate off the metabolic pathway?
a single enzyme (regulatory enzyme
Most metabolic reactions use _____
chemical energy
_____ is held in the bonds between atoms of molecules and is released when _____
chemical energy
these bonds break
when do cells burn glucose
in a process/reaction called oxidation
Cells can only capture ____ of the energy released from breaking chemical bonds in cellular respiration to make ATP
40%
An ATP molecule includes a chain of 3 phosphates, when _____ is broken off the _____ is released and the molecule is now ADP
the terminal phosphate;
ATP molecule energy
How can ADP be converted back into ATP
cellular respiration
oxidation _____ electrons
loses
reduction _____ electrons
gains
what is the function of this enzyme: helicase
“unzipping”
breaks H bonds between nucleotides into two strands
what is the function of this enzyme: primase
“builder”
duplicates the DNA
what is the function of this enzyme: DNA polymerase
binds to the primer and makes the new strand
puts DNA where RNA was
what is the function of this enzyme: exonuclease
removes all the RNA primers
what is the function of this enzyme: DNA ligase
seals the fragments in both strands
What do nucleotides to
pair with complementary bases to form new strands
what are nitrogen bases
molecules in DNA that pair up during replication
what are hydrogen bonds
bases are paired together with hydrogen bonds
what is a double helix
twisted DNA that unwinds to form 2 new strands
what is the replication fork
where it started to split open from the helicase
what is the DNA template
og DNA that helps creat complementary strands
what is 5’ to 3’
determines how each strand of DNA is replicated
HAS TO GO IN TRAIT ORDER
what is the leading strand
made continuously from 5’ to 3’
what is the lagging strand
strand copied in fragments(okazaki fragments)
what is a primer
the new DNA made by the primase
what is the complementary strand
not the same DNA but complement each other
what are okazaki fragments
fragments formed by lagging strand
what is semi-conservative
each DNA molecule is made up of one og and one new
what are the four DNA bases
adenine
thymine
cytosine
guanine
what is replication
copying of DNA during interphase
