Unit 1 Revision: Cloze Exercise 1.
Cell Function & Inheritance
Proteins, Enzymes, Nucleic Acids & Protein Synthesis
WORDBANK:
BONDS,
ADENINE,
CATALYSTS,
AMINO
CODE,
ACIDS,
ANTIBODIES,
ANTI-CODONS,
CO-FACTOR,
COMPETITIVE,
CODONS,
COMPLEMENTARY, CONJUGATED, CYTOSINE, DECREASES, DEOXYRIBOSE,
ENDOPLASMIC, ENZYMES, ERROR, EXTRACELLULAR, FIBROUS, GLOBULAR,
GOLGI,
GUANINE,
HELIX,
INHIBITOR,
INTRACELLULAR,
METABOLIC,
NITROGEN, NUCLEOTIDES, PEPTIDE, POLYPEPTIDE, PROTEIN, RIBOSOMES,
SECRETED, SUBSTRATE, THYMINE, TRANSCRIBED, TRANSFER, TRIPLET,
URACIL, VESICLES.
1. Enzymes
are
biological
biochemical
which speed up
the
enzymes
work
reaction.
cells;
rate
of
a
inside
enzymes function outside cells.
2. A molecule of enzyme is composed of
which is
and key.
. It has an active site
to the molecular structure of its substrate, like a lock
3. To function efficiently an enzyme requires a suitable temperature, an
appropriate
pH
and
an
adequate
supply
4. An inhibitor is a substance that
of
.
or halts the rate of an
enzyme-controlled reaction. A
inhibitor is affected by both
concentration of inhibitor and concentration of substrate; a non-competitive
inhibitor
is
affected
by
concentration
of
5. Many enzymes require the presence of a
properly;
some
enzymes
6. Each stage in a
genetic
fault
occurs,
inborn
are
an
activated
only.
to function
by
other
.
pathway is controlled by an enzyme. If a
enzyme
may
be
absent
causing
an
of metabolism.
7.
In
addition
to
contain
carbon,
hydrogen
and
oxygen,
proteins
always
.
8. A protein consists of sub-units called
together by
which are joined
bonds to form polypeptides.
9. A molecule of
protein consists of
arranged in parallel. It has a structural function.
chains
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
associated with a non- protein part.
protein
consists
of
globular
protein
12. DNA consists of two strands twisted into a double
strand
is
of
composed
of
.
nucleotide
consists
sugar, phosphate and one of four types of base (
, thymine,
13.
Each
. Each
Adenine
always
with
pairs
, and cytosine).
with
;
guanine
always
pairs
.
14. RNA consists of a single strand of nucleotides.
place of thymine; ribose replaces
is found in
.
15. The bases along a DNA strand take the form of a molecular language called
the genetic
particular amino acid.
. Each
of bases codes for a
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
carrying a specific amino acid.
RNA(tRNA) each
17. Protein synthesis occurs in ribosomes; mRNA's triplets of bases,
called
are "read" and matched to 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
into
.
where
it
is
processed
and
packaged
20. Some protein is
out of the cell by vesicles moving towards
and fusing with the plasma membrane.
ANSWERS: Unit 1 Revision: Cloze Exercise.
Cell Function & Inheritance
Proteins, Enzymes, Nucleic Acids & Protein Synthesis
1. Enzymes are biological catalysts which speed up the rate of a biochemical
reaction. Intracellular enzymes work inside cells; Extracellular enzymes function outside cells.
2. A molecule of enzyme is composed of protein. It has an active site which
is complementary to the molecular structure of its substrate, like a lock and key.
3. To function efficiently an enzyme requires a suitable temperature, an appropriate pH and
an
adequate
supply
of substrate.
4. An inhibitor is a substance that decreases or halts the rate of an enzyme-controlled
reaction. A competitive inhibitor is affected by both concentration of inhibitor and
concentration of substrate; a non-competitive inhibitor is affected by concentration
of inhibitor only.
5. Many enzymes require the presence of a co-factor to function properly; some enzymes are
activated
by
other enzymes.
6. Each stage in a metabolic pathway is controlled by an enzyme. If a genetic fault occurs, an
enzyme
may
be
absent
causing
an
inborn error of
metabolism.
7. In addition to carbon, hydrogen and oxygen, proteins always contain nitrogen.
8. A protein consists of sub-units called amino acids which are joined together
by peptide bonds to form polypeptides.
9. A molecule of fibrous protein consists of polypeptide chains arranged in parallel. It has a
structural
function.
10. A molecule of globular protein consists of polypeptide chains folded into a spherical
shape. Some are structural in function; others act as enzymes, hormones or antibodies.
11. A molecule of conjugated protein consists of globular protein associated with a nonprotein
part.
12. DNA consists of two strands twisted into a double helix. Each strand is composed
of nucleotides. Each nucleotide consists of deoxyribose sugar, phosphate and one of four
types
of
base
(adenine,
thymine, guanine,
and
cytosine).
13.
Adenine
always
pairs
with thymine;
guanine
always
pairs
with cytosine.
14. RNA consists of a single strand of nucleotides. Uracil is found in place of thymine; ribose
replaces deoxyribose.
15. The bases along a DNA strand take the form of a molecular language called the
genetic code.
Each triplet of
bases
codes
for
a
particular
amino
acid.
16. Messenger RNA (mRNA) is transcribed from a strand of DNA and carries this genetic
message from the nucleus out into the cytoplasm. At a ribosome mRNA meets molecules
of transferRNA(tRNA)
each
carrying
a
specific
amino
acid.
17. Protein synthesis occurs in ribosomes; mRNA's triplets of bases, called codons are "read"
and matched to tRNA's anti-codons. This enables peptide bonds to form between adjacent
amino
acids.
18. Rough endoplasmic reticulum (ER) bears ribosomes on its surface; smooth ER lacks
ribosomes.
19. Freshly synthesised protein is transported via the rough ER to the Golgi apparatus where
it
is
processed
and
packaged
into vesicles.
20. Some protein is secreted out of the cell by vesicles moving towards and fusing with the
plasma membrane.