Higher Biology

Revision Exercise

Unit 1

Cell Biology

Cell Variety / Absorption and Secretion 1) The ____ is the basic unit of life.cell

2) A ___________ organism consists of one cell which possesses a variety of structures enabling it to perform all the functions necessary for the maintenance of life.

unicellular

3) A ____________ organism consists of more than one cell. In advanced animals and plants these are arranged into tissues giving a division of labour.

multicellular

4) _________ in cell structure exists between cells of one type of tissue and cells of different tissues since cells are __________ to perform particular functions.

Variationspecialised

5) Cells absorb molecules in solution by ________, osmosis and active _________.

diffusiontransport

6) The cell wall surrounding plant cells is made of ________ and is ______ permeable to solutions. It prevents the cell from ________ when water is absorbed.

cellulose freely bursting

7) The plasma __________ surrounding the living contents of all cells is selectively __________. It consists of protein and ____________ molecules thought to be arranged as in the fluid _______ model.

membranepermeable phospholipid

mosaic

8) Tiny channels in the plasma membrane make it _______ and allow the _______ transport of small molecules by diffusion and osmosis along a concentration gradient.

porous passive

9) Other chemical substances such as ions are ________ transported across the plasma membrane _______ a concentration gradient by _______ carriers. This process requires _______.

activelyagainst

protein energy

Respiration

1) _____ is a high energy compound able to release and _________ energy when it is required for cellular processes.

ATP transfer

2) ATP is regenerated from _____ and inorganic phosphate by the process of _______________ using energy released during respiration.

ADPphosphorylation

3) _________ involves the removal of hydrogen from a substrate and the release of energy; _________ involves the addition of hydrogen to a substrate and the consumption of energy.

Oxidationreduction

4) _________ is a biochemical pathway common to aerobic and _________ respiration. It involves the breakdown of glucose to _______ acid in the cytoplasm of a cell with the net gain of two ATP.

Glycolysisanaerobic pyruvic

5) In the presence of ______, aerobic respiration occurs in the central ______ of mitochondria where the respiratory substrate is oxidised during ______ Cycle and _________ is released.

oxygenmatrix

Krebs’ hydrogen

6) This hydrogen becomes temporarily bound to ____, a coenzyme which transfers it to the ___________ system on the cristae of ____________ where energy is released and used to form ATP.

NADcytochrome

mitochondria

7) As a result of ________ respiration, one molecule of glucose yields 38 ATP. ______ and CO2 are the final metabolic products.

aerobicWater

8) In the absence of oxygen, anaerobic respiration occurs and one molecule of glucose yields 2 ATP. The final metabolic products are ________ and ______________ in plant cells and _____ acid in animal cells (and some bacteria).ethanol carbon dioxide lactic

Photosynthesis

1) Light is absorbed, reflected and ___________ by a leaf.transmitted

2) The photosynthetic pigments from a leaf can be separated by _______________.chromatography

3) Chlorophyll absorbs light primarily in the ____ and _____ regions of the spectrum of white light. _______ pigments absorb blue-green light.

red blueyellow

4) The quantity of light absorbed by a pigment at different wavelengths of light can be presented as a graph called an __________ spectrum; the rate of photosynthesis that occurs in a plant at different wavelengths of light can be presented as a graph called an ______ spectrum.

absorption

action

5) Chloroplasts possess internal structures called _______ which contain photosynthetic pigments and are the site of the ______________ stage of photosynthesis. The region between grana is called the _______. It is the site of the ______________ stage of photosynthesis.

grana light-dependent

stromacarbon fixation

6) The light-dependent stage of photosynthesis is called __________. It produces the energy (held in _____) and hydrogen needed for the second stage (carbon fixation).

photolysisATP

7) The second stage consists of a ______ of reactions which brings about the _________ of carbon dioxide using the ATP and _________ from photolysis to form carbohydrate.

reduction hydrogencycle

8) Photosynthesis is affected by temperature, light intensity and _____________ concentration. Its rate is therefore _______ by whichever one of these factors is in short supply.carbon dioxide limited

DNA and its Replication / Protein Synthesis1) DNA consists of two strands twisted into a double ________. Each strand is composed of ____________. Each nucleotide consists of ______________ sugar, phosphate and one of four types of base

( _________, thymine, _________ or cytosine).

helixnucleotides

deoxyribose

adenine guanine

2) Adenine always pairs with _________; guanine always pairs with _________.

thyminecytosine

3) DNA is unique because it is able to reproduce itself by ___________. This allows the genetic message to be passed on from cell to _____ and generation to generation.

replicationcell

4) RNA consists of a single strand of nucleotides. ________ is found in place of thymine; ________ replaces deoxyribose.

Uracilribose

5) The bases along a DNA strand take the form of a molecular language called the genetic _____. Each _______ of bases codes for a particular amino acid.

code triplet

6) 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.

transcribed

ribosome transfer

7) 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. codons anticodons

bonds

8) Rough ____________ reticulum bears ribosomes on its outer surface.

endoplasmic

9) Freshly synthesised protein is transported via the endoplasmic reticulum to the ______ apparatus where it is processed and packaged in ________.

Golgi vesicles

10) Some protein is _________ out of the cell by vesicles moving towards, and fusing with, the plasma membrane.

secreted

11) In addition to carbon, hydrogen and oxygen, proteins always contain ________. nitrogen

12) A protein consists of sub-units called ____________ (of which there are about 20 types) joined together by peptide bonds to form polypeptides.

amino acids

13) A molecule of _______ protein consists of parallel ____________ chains and has a structural function.

fibrous polypeptide

14) A molecule of _________ protein consists of polypeptide chains folded into a spherical shape. Some are structural (eg. Those in the plasma membrane); others act as _________, hormones or __________.

globular

enzymes antibodies

Cellular Defence

1) ________ exhibit living and non-living characteristics and can only reproduce within the living cells of another organism.

Viruses

2) A virus consists of one type of _______ acid surrounded by a coat of _______.

nucleic protein

3) Once inside a host cell, the virus alters the _____ cell’s metabolism to produce many identical copies of itself.

host

4) The two main ________ mechanisms employed by the human body depend on the activities of ______ blood cells.

defencewhite

5) Phagocytes engulf and destroy microbes by ____________ using lysosomes. This is a ____________ response.

phagocytosisnon-specific

6) _____________ recognise antigens on the surface of a microbe and produce ___________. These possess receptor sites which bind to one particular type of ________ rendering it harmless. This is a ________ immune response.

Lymphocytesantibodies

antigen specific

7) Plants do not make antibodies. They defend themselves against invasion by producing toxic compounds such as ________, cyanide and ________.

nicotine tannins

8) Some plants can isolate an area of injury by secreting sticky ______.resin

End