What You Should Know
Chapters 1 to 3
1. Enzymes are biological ______________ which speed up the rate
of a biochemical reaction. ______________ enzymes work inside
cells; _______________ enzymes work outside cells.
2. A molecule of enzyme is composed of _____________. It has an
active site which is __________________ to the molecular
structure of its substrate, like a lock and key.
3. To function efficiently an appropriate enzyme requires a suitable
temperature, an appropriate pH and an adequate supply of
_________________.
4. An inhibitor is a substance that ______________ or halts the
rate of an enzyme-controlled reaction. A __________________
inhibitor is affected by both conc. of inhibitor and conc. of
substrate; a non-competitive inhibitor is affected by conc. of
_____________ only.
5. Many enzymes require the presence of a ______________ to
function properly; some enzymes are activated by other
_____________.
6. Each stage in a ____________ pathway is controlled by an
enzyme. If a genetic fault occurs, an enzyme may be absent
causing an inborn ___________ of metabolism.
7. In addition to carbon, hydrogen and oxygen, proteins also contain
_____________.
8. A protein consists of sub-units called ______________ which are
joined together by _____________ bonds to form polypeptides.
9. A molecule of _____________ protein consists of
____________ chains arranged in parallel. It has a structural
function.
10. A molecule of ______________ protein consists of polypeptide
chains folded into a spherical shape. Some are structural in
function; others act as enzymes, hormones or
_________________.
11. A molecule of ________________ protein consists of globular
protein associated with a non-protein part.
12. DNA consists of 2 strands twisted into a double ___________.
Each strand is composed of ____________. Each nucleotide
consists of __________________ sugar, phosphate and 1 of 4
types of base (________________, thymine,
___________________ or cytosine).
13. Adenine always pairs with _______________; guanine always pairs
with _________________.
14. RNA consists of a single strand of nucleotides.
_______________ is found in place of thymine; __________
replaces deoxyribose.
15. The bases along a DNA strand take the form of a molecular
language called _____________. Each _____________ of bases
codes for a particular amino acid.
16. Messenger RNA (mRNA) is ____________ from a strand of DNA
and carries this genetic message from the nucleus out into the
cytoplasm. At a _____________mRNA meets molecules of
_____________ RNA (tRNA) each carrying a specific amino acid.
17. Protein synthesis occurs in ribosomes; mRNA’s triplet of bases,
called __________, are ‘read’ and matched by tRNA’s
_______________. This enables peptide _________ to form
between adjacent amino acids.
18. Rough __________________ reticulum (ER) bears ribosomes on
its surface; smooth ER lacks ribosomes.
19. Freshly synthesised protein is transported via the rough ER to the
___________ apparatus where it is processed and packaged into
_____________.
20. Some protein is _____________ out of the cell by vesicles moving
towards and fusing with the plasma membrane.
Word Bank
Adenine
Amino acids
Antibodies
Anticodons
Bonds
Catalysts
Code
Codons
Co-factor
Competitive
Complementary
Conjugated
Cytosine
Decreases
Deoxyribose
Endoplasmic
Enzymes
Error
Extracellular
Fibrous
Globular
Golgi
Guanine
Helix
Inhibitor
Intracellular
Metabolic
Nitrogen
Nucleotides
Peptide
Polypeptide
Protein
Ribose
Ribosome
Secreted
Substrate
Thymine
Transcribed
Transfer
Triplet
Uracil
Vesicles