Unit 1 Flashcards
Catalyst
A substance that speeds up the rate of a chemical reaction.
Enzyme
Protein that acts as a biological catalyst.
Active site
The area of an enzyme where the catalysed reaction occurs.
Substrate
The specific substance that an enzyme acts upon.
Denatured
loss of an enzyme’s normal shape so that it no longer functions; caused by a less than optimal pH and temperature.
Competitive Inhibitor
An enzyme inhibitor that competes with substrate for binding at the active site of the enzyme. Success depends on concentration.
Noncompetitive Inhibitor
A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.
Co-enzyme
A chemical that works with an enzyme (e.g. NAD).
Peptide Bonds
The bonds connecting amino acids together to form polypeptide chains.
Primary structure of a protein refers to
the number and sequence of amino acids held together by peptide bonds in a polypeptide chain
Secondary Structure of protein refers to
The coiled shape the polypeptide chain forms as a result of weak hydrogen bonds between certain amino acids
Tertiary Structure of a protein refers to
The shape of the coiled polypeptide chain forms when further bonding causes it to fold or twist
Striated Muscle
A muscle that appears banded; also called skeletal muscle.
Actin
Thin filament in muscle.
Myosin
Thick filament in muscle.
Sliding Filament Theory
Theory which says that the myofilaments do not become any shorter during contraction and instead slide over each other.
DNA stands for
Deoxyribonucleic acid.
Nucleotides are
Basic units of DNA molecule, composed of deoxyribose sugar, a phosphate, and one of 4 DNA bases.
Sugar-phosphate Backbone
The alternating chain of sugar and phosphate to which the DNA and RNA bases are attached.
Hydrogen Bonds
Weak chemical bonds that hold nucelotides together.
Nucleotide Pairing
Principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine.
Double Helix
Two strands of nucleotides wound about each other; structure of DNA.
RNA
Ribonucleic acid.
RNA Nucleotide
Ribose sugar, one of 4 RNA bases and a phosphate.§
Base A is
Adenine
Base T is
Thymine
Base U is
Uracil
Base C is
Cytosine
Base G is
Guanine
mRNA is
Messenger ribonucleic acid.
Codon
Three-nucleotide sequence on mRNA that codes for a single amino acid.
tRNA is
Transfer ribonucleic acid.
Anti- Codon
Group of three bases on a tRNA molecule that are complementary to an mRNA codon.
The Nucleolus controls the
synthesis of RNA and other components needed to build ribosomes
Ribosome acts as site where
tRNA and mRNA meet protein is synthesized.
Protein always contains what four elements
Carbon, hydrogen, oxygen, nitrogen.
In addition to the CHON elements what other element does protein often contain
Sulphur
RER stand for?
Rough Endoplasmic Reticulum.
Rough Endoplasmic Reticulum
Provides a large surface area for chemical reactions to occur upon and a pathway for the the transport of materials.
Golgi Apparatus
Processes and packages complex molecules ready for discharge from the cell.
Golgi Vesicle
Carries complex molecules to plasm membrane for discharge.
The RER is located close to the nucelus so that the mRNA
doesn’t have to travel far to reach it.
Lysosome
Contains enzymes which digest worn out organelles and microorganisms. Example - Macrophages
Nucleus
Contains DNA, the genetic instructions to make proteins and control inherited characteristics.
Smooth Endoplasmic Reticulum
plays various roles such as the site of enzyme reactions which produce steroid hormones.
Mitochondria
where aerobic respiration occurs, power station of cell
An optical microscope can magnify
500,000 times
Transcription takes place in the
nucleus
Transcription uses what as a template?
DNA
The product of transcription is
mRNA
Translation takes place in the
ribosomes
Translation uses what as a template?
mRNA
The product of translation is
tRNA
The sub-units used in Transcription are
RNA nucleotides
The transcription sequence is determined by
DNA
The Translation sub-units used are
RNA & Amino Acids
The Translation sequence is determined by
mRNA
The number of nucleotide trends present in one molecule of RNA is
1
The number of nucleotide trends present in one molecule of DNA is
2
In RNA the complementary base pair of Adenine is
Uracil
In DNA the complementary base pair of Adenine is
Thymine
The name of the sugar present in an RNA nucelotide molecule is
Ribose
The name of the sugar present in a DNA nucelotide molecule is
Deoxyribose
A triplet of bases is called a
Codon
Each amino acid is coded for by
3 bases
The first step of Transcription is
DNA becomes unwound
The second step of Transcription is
The weak Hydrogen bonds break, DNA molecules unzips and the bases are exposed
The third step of Transcription is
The three DNA nucleotides joins with the complementary base pair
The fourth step of Transcription is
Weak Hydrogen bonds form between bases
The fifth step of Transcription is
Peptide bonds join the phosphate and sugar
The sixth step of Transcription is
New daughter DNA molecule winds up into double helix
Protein Synthesis is the
transcription of DNA into mRNA
The requirements for transcription are:
DNA template, ATP, Enzymes, RNA nucleotides
The DNA leaves the nucleus through
a nuclear membrane pore
The first step in Transcription is
DNA unzips
The second step in Transcription is
Weak Hydrogen bonds break
The third step in Transcription is
Free RNA nucleotides line up opposite complementary bases
The fourth step in Transcription is
Weak Hydrogen bonds form between bases (Temporary)
The fifth step in Transcription is
Strong bonds form between sugar and phosphate of RNA (RNA polymerase)
The sixth step in Transcription is
Weak Hydrogen bonds break and mRNA dissociates from DNA
Transfer RNA is written as
tRNA
An anti codon is complementary to a
codon
Requirements for Translation are
mRNA, Ribosomes, tRNA, Amino Acids, Enzymes and ATP
2 kinds of cell
prokaryotic and Eukaryotic
Prokaryotic cell is a cell
without a nucelus
A Eukaryotic cell is a cell
with nucleus
Fluid in the rough endoplasmic reticulum helps what travel easily?
Protein
A competitive inhibitor is affected by both
Concentration of inhibitor and concentration of substrate
A non competitive inhibitor is affected by only
concentration of inhibitor
Two types of protein are
Fibrous and globular
A fibrous protein is when
Several polypeptides link in parallel lines by bonds between them.
3 examples of a fibrous protein are
Elastin used in the wall of large arteries, collagen used in bone and keratin used in hair
Globular protein is when
Several polypeptide chains are folded together into a spherical shape.
3 examples of globular proteins are
Enzymes, hormones and antibodies
The quaternary structure is the fourth structure of protein and occurs when
Different polypeptide chains combine sometimes with a non protein part
Muscle fibre is made up of lots of smaller fibres called
Myofibril
An example of a conjugated protein is
Haemoglobin
When a muscle fibre contracts
actin filaments slide over myosin filaments towards the centre.
The thick muscle filament is
Myosin
The thin muscle filament is
actin
Biochemical reactions that occur inside cells are controlled by
intracellular enzymes
Biochemical reactions that occur outside the cells are controlled by
extracellular enzymes
Factors that affect enzyme rate are:
Temperature, pH and supply of substrate
The number of substrate molecules that can be acted upon by an enzyme is called its
turnover number
Complementary base pairs are joined by
weak hydrogen bons
In RNA Uracil replaces
Thymine
Uracil pairs with
Adenine