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A-Level OCR Biology > Module 2 - Biology > Flashcards

Module 2 - Biology Flashcards

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1
Q

DNA sequence in genes code for polypeptide molecules such as pepsin and titin.
Explain why a process known as transcription is necessary for polypeptide synthesis.

A

Transcription is necessary for polypeptide synthesis because the gene is copied to the mRNA. And the RNA goes to the ribosomes for polypeptide synthesis as the DNA is too large to fit through the nuclear pores.

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2
Q

Titin is a fibrous protein. Pepsin is a globular protein. Compare the properties and functions of fibrous proteins and globular proteins in the human body.

A

Fibrous protein are insoluble, elongated strands, strong and flexible. They are used for things like protection, e.g. keratin in skin, hair and nails.
Globular protein is soluble, spherical in shape and a tertiary structure.
It is used to package DNA, and transport substances in blood. e.g haemoglobin in RBC carry oxygen.

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3
Q

State the role of a gene

A

It codes for one or more polypeptide

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4
Q

Explain how the structure of DNA allows replication

A

DNA is double stranded and both strands act as templates.
The hydrogen bonds between the complementary base pairings can easily be broken allowing replication to occur.
However the hydrogen bonding between A&T and C&G are different.
There are 3 H bonds in C&G and 2 H bonds between A&T.

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5
Q

Explain why phenolphthalein indicator was able to detect the breakdown of triglycerides.

A

When triglycerides breakdown they form fatty acids. More breakdown means the pH falls which the indicator can detect.

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6
Q

What is a triglyceride

A

Triglyceride is made up of a glycerol and 3 fatty acids.

It usually has a high ratio of Hydrogen to Oxygen

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7
Q

Explain how the structure of phospholipids allow them to form the bilayer of a plasma membrane

A

Phospholipids have a hydrophobic tail and hydrophilic heads. The hydrophilic heads form H bonds with the water and the hydrophobic tails face towards each other.

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8
Q

What is the structure of an amino acid.

A

Central Carbon attached to Carboxyl group (COOH) , Amino group (NH2) and side chain (R)

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9
Q

Orlistat is a drug that directly reduces the breakdown of fat in the small intestine. This reduction in breakdown leads to less fat being absorbed into the body.
Suggest the mechanism by which orlistat reduces the breakdown of fat.

A

Enzyme Inhibitor

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10
Q

Define the term balanced diet

A

Balance diet means consuming nutrients in the correct proportions

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11
Q

Suggest and explain why over consumption of milk and beef can lead to malnutrition.

A

Milk and beef are both triglycerides and both contain large amounts of energy, more than what a human needs.
Over consumption increases fat storage which in turn leads to obesity and other health conditions.
Eating lots of dairy and meat could also mean the diet is not balanced anymore.

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12
Q

What are purines and pyrimidines.

A

Purines have 2 carbon rings - Adenine and Guanine

Pyrimidines have a carbon ring - Cytosine and Thymine

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13
Q

DNA carries the genetic code which is non overlapping and degenerate.
What does non overlapping and degenerate code mean?

A

Each nucleotide is only part of one triplet of bases and more than one triplet codes for a amino acid.

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14
Q

What is the correct definition of the term coenzyme?

A

A non protein organic molecule, not permanently attached to an enzyme but needed to allow the enzyme to function

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15
Q

Explain why onion root tips are used to view cells undergoing mitosis.

A

It is where the cells are able to divide , as it is a meristem, and no chloroplasts are present.

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16
Q

Suggest a stain that a student can use to highlight the nuclei of cells during mitosis

A

Methylene blue

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17
Q

Carl Woese suggested a new top level taxon - domain.
He used his results from studying RNA
Name the cell component that appears in organisms of all 3 domains that Woese suggested.

A

Ribosomes

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18
Q

One of the domains is called Eukarya.

Name the other 2 domains

A

Bacteria

Archaea

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19
Q

State 2 defining features of all members of the domain Eukarya

A

Nucleus
Linear DNA
80s ribosomes

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20
Q

Which stage in the cell cycle is DNA polymerase most active

A

S phase

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21
Q

Describe the function of DNA polymerase

A

Make phosphodiester bonds between adjacent nucleotides.

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22
Q

What is the oder of increasing complexity of organisation within an organism?

A

Cell –> Tissue –> Organ –> Organ System

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23
Q

What elements are found in proteins?

A

Carbon, Hydrogen, Oxygen. Nitrogen, Sulphur

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24
Q

Human pancreatic lipase breaks the bonds between fatty acids and glycerol.
What name is given to this reaction>

A

Hydrolysis

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25
Q

A zygote undergoes rapid cell division.

Explain why the type of nuclear division in a zygote is mitosis and not meiosis.

A

Mitosis is used for the growth of a zygote where it needs to have identical genetic information.

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26
Q

Explain the role of embryonic stem cells in the development of the embryo.

A

Embryonic stem cells are undifferentiated cells, they can differentiate into anything and become specialised in its particular function - developing the foetus.

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27
Q

A blastula is an animal embryo at an early stage of development. As the blastula develops, it becomes a hollow ball of cells with an inner cell mass; which is a source of embryonic stem cells.
Explain why the cells of the inner cell mass are not totipotent stem cells.

A

They are not totipotent because they cannot form whole organisms. They cannot form some tissues such as the placenta
Blastula are pluripotent

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28
Q

Collagen molecule has 3 polypeptide chain each with 1050 amino acids, wrapped into a triple helix.
Describe and explain why collagen is a fibrous protein.

A

Collagen is a fibrous protein because it is a long chain of amino acids.. It is strong and flexible and it is insoluble. It has a structural function to provide strength.

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29
Q

Suggest why collagen is such a strong molecule

A

There are many hydrogen bonds between the polypeptides

There are crosslinks between collagen molecules

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30
Q

What happens in a RER

A

Translation of some proteins takes place in a eukaryotic cell

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31
Q

Describe the structure of the rough endoplasmic reticulum

A

It has a phospholipid bilayer and there are a network of membranes enclosing a fluid filled space. The surface is covered with ribosomes.

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32
Q

Explain the role of the membrane in the RER

A

Compartmentalisation and separates synthesised proteins from the cell cytoplasm

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33
Q

Explain how the nucleotides in a DNA molecules are arranged as two polynucleotide strands.

A

DNA molecules are made up of nucleotides. These are held together by phosphodiester bonds.
There are hydrogen bonds between the complementary bases. 2 hydrogen bonds between A and T and 3 hydrogen bonds between C and G.
Two antiparallel (running in opposite directions) polynucleotide strands twist to form the DNA double-helix.

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34
Q

Name 2 enzymes involved in DNA replication

A

helicase - separating

DNA ligase - joining

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35
Q

Explain why enzymes are essential to all organisms.

A

Enzymes are biological catalyst which speed up the reaction and lowers the activation energy so reactions can take place at low temperatures.

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36
Q

what is a protoctist

A

An eukaryotic organism

It has a nucleus but no cell wall

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37
Q

State 3 changes that the student would need to ensure to do / improve when doing a biological drawing.

A

The label lines should not cross
There should be no arrowheads
No shading or colouring

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38
Q

Both a TEM and a SEM can be used to view the same cell. However, the images formed will be different.
Compare the resolutions of these microscopes and the images formed by them. [4]

A

TEM has a higher resolution between 0.05 and 2nm. It shows the cells organelles such as the nucleus and the mitochondria.
SEM has a lower resolution between 5 - 50nm and it shows the surface of the cell rather than the organelles. However it does provide a 3D image.

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39
Q

Where are erythrocytes and neutrophils formed?

A

In the bone marrow

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40
Q

What is one of the places ciliated epithelial cells are found in?

A

Trachea

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41
Q

The cell wall of the guard cell is thicker or thinner on the side furthest away from the stoma?

A

Thinner

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42
Q

Erythrocytes and neutrophils are both examples of specialised blood cells.
Squamous and ciliated epithelial cells are also examples of specialised cells.
Describe how each of these four cells is specialised for its function. [6]

A

Erythrocytes are red blood cells. They are specialised because they have no nucleus and have biconcave discs to increase the surface area to volume ratio. This means they can carry more oxygen to transport around the body. In addition they are flexible, meaning they can fit through narrow gaps of the capillary tubes.
Neutrophils are white blood cells. They have a multilobed nucleus making it easier for them to squeeze through small gaps to get to the site of infections. The granular cytoplasm contains main lysosomes that contain enzymes used to attack pathogens.
Squamous epithelial cells are very thin and one cell thick, therefore rapid diffusion can occur and exchange of gases at the alveoli
Ciliated epithelial cells have cilia which move in rhythm to move mucus and trapped pathogens.

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43
Q

Suggest why goblet cells have large number of mitochondria.

A

They provide a lot of energy

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44
Q

Suggest how the role of the Golgi apparatus is relevant to the function of the goblet cell.

A

The Golgi apparatus packages protein and aids secreting the mucus in exocytosis

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45
Q

Sjogren’s syndrome is a rare condition that can reduce the production of mucus.
Suggest how the upper respiratory tract of a place with Sjogren’s syndrome might be affected.

A

More infections leading to coughing

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46
Q

How are two amino acids joined together

A

Peptide bonds

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47
Q

The process of esterification leads to the formation of ester bonds during the production of triglycerides.
Describe what is meant by the term esterification

A

The reaction between carboxylic acid and alcohol. It is a condensation reaction and removed H20

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48
Q

Explain the meaning of the phrase semi conservative replication

A

Semi conservative replication is when each strand of DNA acts as a template strand for a new double helix

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49
Q

DNA ligase is one enzyme involved in the replication of DNA

State 2 other enzymes involved and describe their functions

A

DNA helicase unzips the DNA molecules by breaking the hydrogen bonds and separating the 2 strands
DNA polymerase forms phosphodiester bonds forming the sugar phosphate backbone

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50
Q

Give one way that an image produced by a laser scanning confocal microscope differs from that produced by an electron microscope

A

Laser scanning confocal has a Lower resolution compared to electron microscope
It also allows live species to be viewed
Uses fluorescent tags

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51
Q

The use of stem cells is being evaluated for the treatment of certain human diseases
Name 2 potential sources of human stem cells and for one source, describe an ethical issue associated with the use of stem cells.

A

Embryonic and bone marrow. The ethical issue with use embryonic sources is that embryos die, some may believe that lives are being killed

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51
Q

What observations are made at prophase

A

In prophase chromosomes are condensed

Nucleolus is not visible

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52
Q

In meiosis, metaphase 1 occurs

Explain how the organisation of homologous chromosomes during metaphase 1 increases genetic variation

A

The organisation of homologous chromosomes increases genetic variation because there is random assortment
The homologous chromosomes line up on the equator and one of the homologous pair end up facing either pole.
Causing each chromosome to be genetically different

53
Q

Glucose is a biological molecule required by cells for cellular respiration
State the physical property of glucose that allows it to be easily transported in the bloodstream

A

Glucose is soluble in water

54
Q

Multicellular organisms need to be able to convert monosaccharides into polysaccharides and back again
Mammals convert the monosaccharide glucose into a highly branched polysaccharide called glycogen, which gets stored in liver cells.
Explain why mammals store glycogen instead of glucose.

A

Glycogen is compact and can be stored in a small space
It can store lots of energy
It is insoluble so has no effect water potential of cell

55
Q

Humans use the enzyme alpha - amylase to break down polysaccharides in food for absorption into the blood.
The gene is transcribed in the nucleus and translation occurs on the rough endoplasmic reticulum in cells of the salivary gland.
Describe how the molecule is prepared and secreted by cells of the salivary gland after translation has taken place.

A

Modification occurs at the Golgi apparatus
It is packaged into secretory vesicle and this moves along the cytoskeleton
The vesicle fuses with the cell surface membrane
Secretion occurs through exocytosis

56
Q

Plasma membrane are partially permeable
One molecule that crosses membranes easily is the steroid hormone progesterone which is produced in the ovaries from cholesterol
Explain why progesterone can move across membranes

A

Progesterone is hydrophobic so diffuses through the phospholipid bilayer

57
Q

ATP is made up of phosphate groups and 2 other molecules

Name 2 other molecules

A

Ribose

Adenine

58
Q

Explain what standard deviation shows

A

Standard deviation shows spread of data around the mean

59
Q

A polypeptide chain of amino acids is made. What is the bond between each amino acid and what reaction does it undergo

A

Peptide bond

Condensation reaction

60
Q

What is the formula for Rf

A

Distance from origin to spot / distance from origin to solvent front

61
Q

A cytoskeleton is present in all eukaryotic cells.

State how the cytoskeleton moves organelles around the cell.

A

Cytoskeleton uses microtubules to move organelles around the cell

62
Q

Epithelial cells in the airways of mammals play an essential role in defences against pathogens
Explain the function of epithelial cells in the airways of mammals in the defence against pathogens and suggest the importance of the cytoskeleton in carrying out this function

A

Epithelial cells contain goblet cells which produce mucus that can trap pathogens. Then the cilia, hair like structures, move the mucus with the trapped pathogens away.
The cytoskeleton is important in this process as it makes up the cilia

63
Q

Copper (II) ions act as irreversible non competitive inhibitor of the enzyme catalase.
Describe how a non competitive inhibitor works to inhibit the activity of an enzyme

A

Non competitive inhibitor binds to the allosteric site.
This causes the active site to change shape
Therefore the enzyme substrate complex cannot be formed

64
Q

What bond holds the alpha glucose and the fructose together.

A

1,6 glycosidic bond

65
Q

What will not effect the rate of phosphodiester bond formation

A

Length of DNA molecule

66
Q

In human cells, the tumor suppressor gene codes for a protein that interrupts the cell cycle and prevents the copying of damaged DNA.
Which stage could this gene interrupt

A

G1 phase

67
Q

Outline the properties of water which make it an ideal habitat for an amphibian

A

It is a good solvent
Ice is less dense than water
It has high specific heat capacity

68
Q

The student investigates the effect of cell size on the rate of diffusion using two agar cubes and phenolphthalein indicator.
State 2 ways they can ensure their results are confident

A

Repeat the practical
Calculate a mean
Pick out any anomalies

69
Q

Explain why the surface area to volume ratio of an organism determines whether it needs a circulatory system

A

Larger organisms have a smaller SA to volume ratio, therefore diffusion is slower as it has to travel longer distances
So metabolic demands are higher and nutrient supply is slower
therefore it needs a circulatory system

70
Q

Living organisms have many uses for triglycerides, one of which is the production of phospholipids
Name 3 other functions of triglycerides in living organisms

A

Thermal insulation
Electrical Insulation
Energy storage

71
Q

As the number of hydrogen decreases in methyl esters, the melting point decreases. Why is this?

A

There is a more kinked chain.

Less hydrogen bonds

72
Q

Explain how the fatty acids in phospholipids allow the formation of membranes

A

Fatty acids are hydrophobic so the tails point inwards forming a phospholipid bilayer where the head points outwards.

73
Q

Suggest why cell T and the cells surrounding it, can be classified as parenchyma tissue.

A

The cells are working together with similar functions

74
Q

What are the 2 similarities and differences between the DNA nucleotide and a molecule of ATP.

A

DNA and ATP both have adenine base and pentose sugar
ATP has 3 phosphate groups, DNA has 1
ATP has ribose sugar, DNA has deoxyribose sugar

75
Q

Explain the Benedicts test for reducing sugar

A 
Add Benedicts Reagent (blue) to sample 
Heat using water bath 
If positive coloured precipitate 
Blue -- Green -- Yellow -- Orange -- Red
Higher conc, further colour change
76
Q

Explain the Benedicts test for non reducing sugar

A 
Add dilute HCL 
To neutralise add sodium hydrogen carbonate 
Carry out reducing sugars test 
Positive then non reducing present 
Negative then stay blue
77
Q

Explain the Iodine test for Starch

A

Add iodine dissolved in potassium iodide solution
Starch present then brown-orange to blue black
Starch not present then stays brown-orange

78
Q

Explain the Biuret test in Protein

A

Add NaOH solution to make alkaline
Add Copper(II) sulphate solution
Protein present then turns purple
Protein not present then stays blue

79
Q

Explain the Emulsion test for lipids

A

Shake test substance with ethanol
Pour solution into water
Lipid present - solution will turn milky
Lipid not present - solution will stay clear.

80
Q

State the level of taxonomic group after Animal Kingdom

A

Phylum
Class
Order
Family

81
Q

State 3 reasons why the three-domain classification system is now used in preference to the five-kingdom system.

A

The 3 domains fit phylogeny better.
There are differences between bacteria and archaea such as having different cell membranes
Eukaryotes all have a nucleus.

82
Q

In the past roe deer’s main natural predator in Britain was a large carnivore of the cat family. The lynx became extinct in Britain around 1000 years ago
Plans are being considered to reintroduce the Eurasian lynx from these European populations to the wild parts of Britain to improve biodiversity.

Suggest one reason why some people might object to this reintroduction

A

Could cause potential danger to local wildlife and the environment may no longer be suitable for lynx

83
Q

The Iberian lynx and Eurasian lynx were once classified within the species, based on their observable features.
In the last 10 years, the Iberian lynx has been reclassified as a separate species within the genus Lynx, on the basis of its phylogeny.

Define the term phylogeny and explain how phylogeny is related to classification. Use the lynx species as examples.

A

Phylogeny is the evolutionary relationship between species.
Phylogeny is the basis of classification, species within the same group have common ancestor.
The lynx are similar as they have been placed in the same genus.

84
Q

Woese carried out a detailed study of RNA molecules in order to draw his conclusions.
Suggest two ways in which the scientific community are likely to have validated Woese’s research

A

Peer review

replication of work by others to see if same results are obtained

84
Q

The Titicaca water frog, Telmatobius culeus, is an aquatic amphibian found in Lake Titcaca in South America
Name the genus of the Titicaca water frog

A

Telmatobius

85
Q

Suggest why it is only in the last 10 years that the Iberian lynx has been classified as a separate species

A

Better technology has evolved

More genetic evidence

86
Q

Discuss the classification of slime moulds and include the range of evidence which this classification might be based on

A

Slime moulds are eukaryotes. This is based on the amino acid sequences.
Amino acid sequence of slime moulds are more similar to plants and fungi than protoctists.

87
Q

A conjugated protein is held together by many different types of bond.
Which bond is not formed when a conjugated protein folds into its quaternary structure

A

Peptide

88
Q

Outline the method of chromatography that will separate the main amino acids in collagen

A

Breakdown the collagen into amino acids
Draw a pencil line close to the end of paper
Place sample on chromatography plate (spot on the line)
Place this into solvent
Dry and repeat

89
Q

A multicellular organism with a cell wall is what kingdom and what would the cell wall be made out of.

A

Plant kingdom

Cellulose

90
Q

A unicellular organism with a cell wall is what kingdom and what would the cell wall be made out of.

A

Fungi

Chitin

91
Q

Describe how the genetic material is arranged in organisms in the same kingdom as a unicellular organism

A

Only one chromosome

92
Q

In mammals the lungs act as the gas exchange system. Various components of this system work together to ensure gas exchange is efficient. Two such components are cartilage and elastic fibres.
State the roles of these 2 components in mammalian gas exchange.

A

Cartilage - Supports trachea

Elastic fibres - recoil of alveoli

93
Q

What equipment do you use to test the thickness of the exchange surface upon diffusion

A

Only use one temperature

Use 2 layers of dialysis tubing

94
Q

How is DNA extracted

A 
Grind a sample to break down cell wall
Mix sample with detergent to break down cell membrane 
Add salt - breaks H bonds 
Add protease - breaks down protein 
Add a layer of alcohol (ethanol) on top 
DNA sample will start forming
95
Q

what type of disease of malaria

A

It is parasitic

96
Q

Suggest how the plasma membrane of D. Discoideum is adapted for cell communication

A

The plasma membrane contain glycolipids

97
Q

State the correct term for the definition:

The detailed structure of cells visible only with an electron microscope

A

Ultrastructure

98
Q

Why is the second division of meiosis different from mitosis

A

the separating chromatids of a pair are not the same.

99
Q

The walls of blood vessels contain a polymer called collagen.

Name the type of monomer from which collagen is made and explain how two such monomers are joined together.

A

The monomer is amino acid, they are joined together by peptide bond

100
Q

The rate of movement of molecules from the plasma membrane towards the centre of living cells is often greater than that seen in the procedure the student carried out even if the cells are kept at the same temperature.

Suggest a reason for this observation.

A

The molecules are moved by cytoskeleton and vesicles

101
Q

describes one specialisation of a sperm cell

A

acrosome contains enzymes to digest outer portion of egg

102
Q

Explain why glucose cannot pass through a cell membrane by simple diffusion.

A

The phospholipids act as a barrier

Glucose molecules are too large

103
Q

the binding site changes shape to fit more closely around the substrate molecule. What theory is this

A

Induced fit

104
Q

Suggest why it is beneficial to the plant for the carbohydrate to be transferred throughout the plant in the form of sucrose rather than as an alternative carbohydrate.

A

sucrose is soluble so can be transported in sap, it is metabolically inactive

105
Q

A student mixed an unknown substance with water and ethanol. A white suspension formed in the tube.
What is this

A

A lipid is formed

106
Q

Discuss the benefits of using stains when making slides for light microscopy.

A

contrast is higher, more internal structures visible

107
Q

DNA replication and transcription are two processes that occur in the nucleus of eukaryotic cells.
* Compare DNA replication and transcription by describing the similarities and differences between the two processes.

(6)

A

Similarities is that DNA unwinds and unzips with the help of helicase enzyme.
Both have complementary base pairings, of A-T, C-G held together by hydrogen bonds.

Differences is that only a small section of DNA (where the gene is located) unzips during transcription, whereas both strands act as templates in replication.
Products are two new daughter strands of DNA in replication and one mRNA strand in transcription.

108
Q

What two substances are required to break the glycosidic bond in lactose?

A

Water

Lactase enzyme

109
Q

State the name given to any inorganic ion that increases the activity of an enzyme.

A

Cofactor

110
Q

A vet is concerned that a llama is unwell. The vet suspects there may be haemoglobin in the urine of the llama.

Explain how the vet could confirm this suspicion.

A

add biuret solution to urine)

observe colour change from blue to purple if protein is present

111
Q

DNA is one of many substances which will dissolve in water. Explain why water is a good solvent.

A

molecules are polar

Polarity enables water molecules to attract solutes

112
Q

A student tried to extract some DNA from a crushed banana at home. DNA dissolves in water but the student realised that they needed to add something to break open the nuclear envelope to release the DNA.

Suggest a suitable substance the student could use to release the DNA, and explain why it should work.

A

Detergent

works as an emulsifier and will break up the plasma membranes

113
Q

Suggest three ways in which the use of embryonic stem cells in research has practical benefits to biological knowledge.

A

test how effective new medicinal drugs are

test for side effects of new drugs

for developmental research

114
Q

State the name of the monomer in cellulose.

A

Beta glucose

115
Q

What does a t test do ?

A

Compares two means

116
Q

Stem cells can specialise to form a variety of cell types.

What other feature is shown by stem cells but not by specialised cells?

A

Ability to divide

117
Q

compare the differences in structure between amylose and cellulose

A

amylose is coiled, cellulose is uncoiled
amylose is alpha glucose, cellulose is beta glucose
amylose is granular, cellulose is fibrous

118
Q

Which properties of cellulose make it suitable for forming cell walls?

A

Strong

hydrogen bonds can be formed between adjacent fibrils

119
Q

Why is the ability of water to act as a solvent important for the survival of organisms?

A

transport medium for reactions

120
Q

Explain why plants are more able to form natural reproductive clones than animals.

A

most plant cells retain ability to differentiate / totipotent;

plants have, meristems

121
Q

Name the enzyme that can be used to convert mRNA to single-stranded DNA.

A

reverse transcriptase

122
Q

Explain how helper T cells act to speed up these processes

A

helper T cells stimulated by antigen-presenting cells

release interleukins which stimulate B cell for clonal expansion

123
Q

Name one structure present in animal cells that is not present in plant cells.

A

Centriole

124
Q

The cytoskeleton in cells consists of microtubules and microfilaments.

Describe the roles of the cytoskeleton.

A

Cytoskeleton maintains shape of the cell
helps movement of cilia
helps with movement of chromosomes

125
Q

Plant and animal cells have different structural features.
The pancreas is an organ that secretes protease enzymes.

Outline how the organelles in pancreatic cells work together to produce and release these protein molecules from the cells

A

The nucleus contains the gene of the protein and produces mRNA.
The RNA leaves the nuclear pores and goes to the ribosomes for protein synthesis as DNA is too large to fit
The vesicles then transport the protein
The Golgi apparatus helps modifies and repackages the protein
the vesicle is transported along the cytoskeleton to the cell surface membrane where it fuses and is ready for exocytosis.

126
Q

What two substances are required to break the glycosidic bond in lactose?

A

Water and lactase enzyme

127
Q

Each gill is supported by a gill arch made of bone. Bone tissue is made of living cells, collagen and an inorganic component.

Explain why bone is described as a tissue and gills are described as organs.

A

tissues have one or few types of cell and perform one/few functions which is what a bone does
A gill is an organ because it consists of several tissues

128
Q

State the term used to describe an ion that is essential for the enzyme to function.

A

Cofactor

129
Q

Name another conjugated protein that contains a haem group.

A

Haemoglobin

A-Level OCR Biology (29 decks)

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