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OCR A level bio > Module 2 > Flashcards

Module 2 Flashcards

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1
Q

Centrioles

A

Structures found in cytoplasm made of microtubules that produce the spindle fibres during mitosis

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2
Q

Chloroplast

A

Organelles found in plants and algae which are site of photosynthesis

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3
Q

Cilia

A

Small hair like structures, projecting from cell surface

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4
Q

Confocal microscopy

A

Microscopy which uses lasers to scan a specimen point to point to produce an image

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5
Q

Cytoskeleton

A

A mesh of protein fibres found in the cytoplasm of eukaryotic cells used for structural support and intracellular transport

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6
Q

Differential staining

A

Multiple different stains to distinguish different parts of specimen

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7
Q

Eukaryotic cell

A

Cell with a nucleus and membrane bound organelles

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8
Q

Flagella

A

Whip like structure found on bacterial cells used for cell movement

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9
Q

Golgi apparatus

A

Found in eukaryotic cells involved in modifying and packaging proteins

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10
Q

Light microscope

A

Microscope which uses a series of lenses to magnify visible light reflecting off a specimen

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11
Q

Lysosomes

A

Membrane bound vesicles found in cytoplasm that contain the hydrolytic enzyme called lysozyme

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12
Q

Magnification

A

How much bigger an image appears compared to an original object calculated using the formula

Image size = actual size x magnification

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13
Q

Mitochondria

A

Organelle found in eukaryotic cell which is site of aerobic respiration

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14
Q

Nuclear envelope

A

Double membrane surrounding the nucleus

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15
Q

Nucleolus

A

Structure in nucleus that contains proteins and RNA and is involved in synthesising new ribosomes

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16
Q

Nucleus

A

Organelle found in eukaryotic cells that store as genetic information of cell as chromosomes and surrounded by nuclear envelope

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17
Q

Plasma membrane

A

A semipermeable lipid bilayer studded with proteins which surround cells

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18
Q

Prokaryotic cell

A

A type of cell which doesn’t contain membrane bound organelles or nucleus

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19
Q

Resolution

A

Ability to distinguish between two points in a specimen

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20
Q

Ribosomes

A

Organelles free in cytoplasm or membrane bound which are involved in synthesis of proteins

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21
Q

Rough endoplasmic reticulum

A

Membrane bound organelle involved in synthesis and packaging of proteins

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22
Q

Scanning electron microscope

A

Microscope which passes a beam of electrons over the surface of a specimen to produce an image

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23
Q

Smooth endoplasmic reticulum

A

Membrane bound organelle involved in lipid synthesis

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24
Q

Transmission electron microscope

A

Microscope with passes a beam of electrons through a sample to produce an image

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25
Q

Adhesion

A

Properties of water molecules which creates an attraction between them and surfaces they are in contact with

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26
Q

What is an amino acid

A

Monomers containing an amino group, carbonyl group and a variable r group

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27
Q

Amylopectin

A

Branched polysaccharide made up of alpha glucose monomers joined by alpha 1-6 glycosidic

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28
Q

Anions

A

Ion with negative charge

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29
Q

Benedicts test

A

Biochemical test used to detect presence of reducing sugar in solution

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30
Q

Biuret test

A

Purple collar when added to solution containing protein

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31
Q

Cellulose

A

Linear polysaccharide that is the main component of the cell wall in plants and made up of many beta glucose molecules joined by beta 1-4 glycosidic bonds

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32
Q

Cations

A

Ion with positive charge

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33
Q

Cohesion

A

Property of water molecules that create an attraction between hem which causes them to stick together

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34
Q

Condensation reaction

A

Reaction that joins two molecules together with the formation of a chemical bonds involving the elimination of a molecule of water

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35
Q

Conjugated protein

A

Protein with a prosthetic group bound to it

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36
Q

Elastin

A

Type of a fibrous protein that allows tissues and structures like blood vessels to stretch and return to original shape

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37
Q

Fibrous protein

A

Class of long chain proteins that are insoluble in water and have structural roles

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38
Q

Globular protein

A

Spherical shaped proteins that are generally water soluble and typically have metabolic roles

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39
Q

Glucose

A

Hexose monosaccharide that is the main respiratory substrate in eukaryotes

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40
Q

Glycogen

A

Highly branched polysaccharide that is used as a main energy storage molecule in animals and is made of alpha glucose monomers joined by a 1-4 glycosidic bonds

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41
Q

Haemoglobin

A

A type of conjugated globular protein used to transport oxygen that is made up of four polypeptide chains each containing a haem prosthetic group

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42
Q

Hexose monosaccharide

A

Simple sugar containing 6 carbon atoms

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43
Q

Hydrogen bonds

A

A weak bond formed between an electropositive hydrogen and and an electronegative atom e.g. o2 and nitrogen

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44
Q

Hydrolysis

A

Breaking a chemical bond between two molecules involving use of a water molecule

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45
Q

Insulin

A

Globular protein hormone that is made in the pancreas in response to detection of high glucose levels in the blood

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46
Q

Iodine test

A

Test that produces a blue/black color when added to a starch containing solution

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47
Q

Keratin

A

A fibrous protein that provides strength to hair and nails

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48
Q

Lactose

A

A disaccharide made of a molecule glucose and galactose joined by a glycosidic bond

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49
Q

Lipid emulsion

A

Produces cloudy emulsion when performed on lipids

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50
Q

Maltose

A

Disaccharide made of two molecules off glucose joined by a glycosidic bond

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51
Q

Pentose monosaccharide

A

Simple sugar with 5 carbon atoms

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52
Q

Phospholipid

A

An amphipathic lipid made from a molecule of glycerol bonded to two fatty acid molecules and a phosphate group

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53
Q

Primary strucure

A

Sequence of amino acids in a protein

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54
Q

Quaternary structure

A

Structure applicable to proteins with multi polypeptide chains that describes the interactions of different chains

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55
Q

Ribose

A

A pentose monosaccharide which composes the backbone of RNA

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56
Q

Saturated fatty acid

A

Fatty acid molecule with only single bonds between carbon atoms

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57
Q

Secondary structure

A

Local interactions of amino acids in polypeptide chain

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58
Q

Solvent

A

Lipid that solutes can dissolve in to form a solution

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59
Q

Starch

A

Polysaccharide used for energy storage in plants that is made up of alpha glucose joined together in forms of amylose and amylopectin

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60
Q

Sucrose

A

Disaccharide made up of a molecule glucose and fructose joined by glycosidic bond

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61
Q

Tertiary structure

A

Way protein folds to make a 3d structure

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62
Q

Triglyceride

A

Type of lipid formed from a molecule of glycerol joined by ester bonds to three fatty acid molecules

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63
Q

Unsaturated fatty acid

A

Fatty acid molecule containing at least one double bond in carbon chain

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64
Q

ATP

A

A nucleotide consisting of ribose molecule joined to nitrogenous base adenine and three phosphate groups

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65
Q

Degenerate

A

Some amino acids can be coded for by different codons

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66
Q

DNA

A

Double stranded polynucleotide that contains the genetic material of an organism and made of deoxyribonucleotide monomers joined together by phosphodiester bonds

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67
Q

DNA nucleotide

A

Monomer which makes up DNA and consists deoxyribose, nitrogen base and phosphate groups

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68
Q

DNA polymerase

A

Enzyme which catalyses the formation of phosphodiester bonds between nucleotides and synthesis of new DNA strand

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69
Q

RNA polymerase

A

Enzyme catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of new RNA strand

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70
Q

Helicase

A

An enzyme which catalyses the unwinding and unzipping of DNA in many processes e.g. replication and transcription

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71
Q

mRNA

A

RNA which carries genetic info from the DNA in the nucleus to ribosomes for translation

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72
Q

Phosphodiester bond

A

Bond which joined nucleotides together to create polynucleotides

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73
Q

Purines

A

Nitrogenous bases which are made up of two rings - adenine and guanine

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74
Q

Pyramidines

A

Nitrogenous bases made up of a single - Cytosine, thymine and uracil

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75
Q

Ribosomal RNA

A

RNA which makes up ribosomes

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76
Q

Semi-conservative replication

A

Replication of DNA to make two new DNA molecules which both contain one new strand and one old from the original

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77
Q

Transcription

A

Synthesising a new mRNA strand from a molecule of a DNA

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78
Q

tRNA

A

RNA which has three hairpin loops, an anticodon for attachment to mRNA codon and an amino acid binding site and used to carry amino acids to the ribosome

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79
Q

Translation

A

Protein synthesis where complementary tRNAs carrying amino acids are brought to each codon in an mRNA molecules as move through ribsome

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80
Q

Activation energy

A

Amount of energy needed for a reaction to happen

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81
Q

Active site

A

Specific region on an enzyme where the substrate binds and reaction occurs

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82
Q

Amylase

A

An enzyme which catalyses the extracellular breakdown of starch

83
Q

Catalase

A

Enzyme which catalyses the intracellular breakdown of hydrogen peroxide into oxygen and water

84
Q

Coenzyme

A

A cofactor which is bound loosely to an enzyme with loose interactions

85
Q

Cofactors

A

Non protein molecule which is needed for effective functioning of an enzyme

86
Q

Competitive inhibitor

A

Molecule which binds to active site of an enzyme and prevents the substrate from binding

87
Q

Cyanide (CN-)

A

A metabolic poison which acts as an irreversible inhibitor of cytochrome oxidase and prevents respiration

88
Q

End product inhibition

A

Enzyme inhibition where the product of an enzyme controlled reaction can bind to enzyme and prevent it from working

89
Q

Enzyme substrate complex

A

Temporary complex formed when substrate binds to active site of an enzyme

90
Q

Enzyme

A

Biological catalyst used to speed the rate of biochemical reactions without being used out or altered permenantly

91
Q

Enzyme product complex

A

Temporary complex formed after enzyme has catalysed the reaction but before products have left active site

92
Q

Extracellular reaction

A

Reaction occuring outside cells

93
Q

Inactive precursor

A

Inactive form of an enzyme that cannot carry out function unless activated

94
Q

Induced fit hypothesis

A

Model of enzyme action that describes how once a specific substrate binds to active site. Enzyme undertakes subtle conformational changes to fit the substrate better

95
Q

Intracellular reaction

A

Reaction within cells

96
Q

Lock and Key Hypothesis

A

Enzyme will only fit substrate that has complementary shape to active site

97
Q

Metabolism

A

Sum of chemical reactions taking place in cell

98
Q

Non competitive inhibitor

A

Inhibitor which binds to different part of an enzyme (allosteric site) and prevents function of enzyme

99
Q

Prosthetic group

A

A cofactor which is bound lightly to an enzyme with strong interactions

100
Q

Substrate specificity

A

Ability to enzyme to catalyse only a specific reaction or a set of reactions which have substrates complimentary to active site of enzyme

101
Q

Temperature coefficient

A

Calculation of increase in reaction rate after a 10 degree temp increase

102
Q

Trypsin

A

An enzyme which catalyses the extracellular breakdown of proteins

103
Q

Active transport

A

Active movement of substances from a low concentration to a higher concentration with the use of energy from ATP

104
Q

Amphipathic

A

Molecule with hydrophobic and hydrophillic parts

105
Q

Cell lysis

A

Bursting of cell usually when uptake of too much water into an animal cell through osmosis

106
Q

Cholestrol

A

Mostly hydrophobic molecule which sits in hydrophobic portion of membrane and regulates membrane fluiditiy

107
Q

Crenation

A

Shrinking of cell when placed in a hypertonic solution due to large amounts of water moving out cell due to osmosis

108
Q

Endocytosis

A

Bulk uptake of substances into the cell invagination of the membrane to form a vesicle trapping the solution inside the cell with the use of energy (ATP)

109
Q

Exocytosis

A

Bulk transport of substances out of cell using a vesicle that fuses with plasma membrane using ATP

110
Q

Faciliated diffusion

A

Net movement of substances from a high conc to a low conc through transport proteins without energy

111
Q

Fluid mosaic model

A

Model which describes membrane structure as sea iof mobile phospholipids studded with proteins

112
Q

Hydrophillic

A

Molecule attracted to water

113
Q

Hydrophobic

A

Molecule which repels water

114
Q

Integral membrane protein

A

Type of membrane bound to membrane with strong interactions

115
Q

Osmosis

A

Net movement of water molecules across a partially permeable membrane from a region of high water potential to a region of lower water potential without the use of energy

116
Q

Peripheral membrane protein

A

A protein that is weakly bound to surface of membrane

117
Q

Phagocytosis

A

Ingestion of solid material by phagocytic cells

118
Q

Phospholipid

A

Lipid formed by condensation of one molecule of glycerol, two fatty acids and one phosphate group

119
Q

Pinocytosis

A

Bulk uptake of liquids into cell using energy in the form of ATP

120
Q

Plasmolysis

A

Effect produced by placing plant cells in a hypertonic solution causing the cell to shrivel from water loss, resulting in membrane pulling away from rigid cell wall

121
Q

Simple diffusion

A

Spreading out of substances from high conc to a lower conc without use of energy

122
Q

Turgid

A

A cell which is swollen due to large amount of fluid uptake

123
Q

Water potential

A

Measure of tendency of water molecules to move to onr strs to another

124
Q

Acrosome

A

Organelle in the head of sperm cells, which is specialised to digest the outer coating of an egg cell during fertilisation

125
Q

Anaphase

A

Third stage in mitosis, where chromosomes are pulled apart to poles of cell by spindle fibres

126
Q

Anaphase 1

A

Third stage in meiosis where chromosomes which make up the bivalent are pulled apart from poles of cell by spindle fibres

127
Q

Anaphase 2

A

Seventh phase of meiosis where chromatids are pulled apart to opposite poles of the cell

128
Q

Anucleate

A

Type of cell without a nucleus

129
Q

Asexual reproduction

A

Production of genetically identical offspring from one parent through mitosis

130
Q

Bivalent

A

Pair of homologous chromosomes

131
Q

Cilated epithelium

A

Type of epithelium which has many fine protusions (cilia) and is specialised for sweeping dirt and debris out the body

132
Q

Crossing over

A

Exchange of genetic material between two chromosmes in a bivalent

133
Q

Cytokenesis

A

Division of cytoplasm at the end of mitosis to produce two new daughter cells

134
Q

Differentiation

A

Process where a cell develops certain features so it is specialised to carry out a certain function

135
Q

Diploid

A

Cells with two copies of each chromosome

136
Q

Erythorcyte

A

An anucleate cell specialised to carry oxygen from lungs around the body RBC

137
Q

G1 checkpoint

A

First checkpoint in cell cycle which commits cell to division under favourable conditions

138
Q

G1 phase

A

First growth phase in interphase where the cell synthesises proteins and dupilicates its organelles and increases in size before DNA replication in S phase

139
Q

G2 checkpoint

A

Second checkpoint in cell cycle, occurs replication of DNA is correct

140
Q

Gametes

A

Sex cells which have haploid nucleus and are produced during meiosis

141
Q

Gene loci

A

Location of gene on chromosome

142
Q

Guard cells

A

Type of cell usually found in plants that is specialised to control the opening and closing of stomata

143
Q

Haploid

A

Cells with only one copy of each chromosome

144
Q

Homologous chromosomes

A

Two chromosomes with similar gene loci but different alleles, one inherited from each parent

145
Q

Independant assortment

A

A source of variation in meiosis where bivalent chromosomes can line up either way round on metaphase plate

146
Q

Interphase

A

Largest part of cell cycle where cells spend time growing , synthesising biomolecules and preparing for mitosis

147
Q

Metaphase checkpoint

A

Checkpoint at end of metaphase, ensures all chromosomes have properly attached to spindle fibres and aligned at metaphase plate

148
Q

Meiosis

A

Cell division used to produce gametes that produce four genetically different haploid daughter cells

149
Q

Meristematic tissue

A

Plant tissue which contains stem cells and usually found in growing regions

150
Q

Metaphase

A

Second stage in mitosis where chromosomes attach to spindle fibres and align at metaphase plate

151
Q

Metaphase 1

A

Second stage of meiosis where bivalent chromosomes align across metaphase plate and independent assortment occurs

152
Q

Metaphase 2

A

Sixth stage of meiosis where recombinate chromosomes align on metaphase plate

153
Q

Mitosis

A

Division of cell to produce two genetically identical cells

154
Q

Multipotent

A

Stem cell which can differentiate into any type of cell within a certain tissue in body

155
Q

Neutrophil

A

Type of white blood cell with multi lobed nucleus which is specialised to engulf and destroy pathogens

156
Q

Organ

A

Group of specialised tissues working together to carry out a specific function

157
Q

Organ system

A

Group of specialised organs working together to carry out specific function

158
Q

Palisade cell

A

Type of cell in leaves of plants which contain chloroplasts to carry out photosynthesis

159
Q

Phloem

A

A tissue found in plants which is specialised for transport of assimilates from their site of production to different parts of plant where they are needed

160
Q

Pluripotent stem cell

A

Type of stem cell which has ability to differentiate to any type of cell in body

161
Q

Prophase

A

First mitosis stage, where nuclear envelope breaks down, the centrosomes move to opposite poles of cell, mitotic spindle begins to form and chromosomes condense

162
Q

Prophase 1

A

First stage of meiosis where the nuclear envelop breaks down, spindle fibres form and chromosomes condense and form bivalents.

163
Q

Prophase 2

A

5th stage of meiosis where nuclear envelope breaks down, spindle fibres form and chromosomes condense

164
Q

Recombinant chromosomes

A

Chromosomes produced by crossing over and exchange of genes during metaphase 1

165
Q

Root hair cells

A

Type of cell that is found in roots of cells which has a large SA and is specialised for the uptake of water and ions from soil

166
Q

S phase

A

Second stage in cell cycle where DNA in cell is replicated

167
Q

Somatic cells

A

Any cells that make up an organism excluding sex cell

168
Q

Sperm cell

A

Male gamete which contains a long tail, an acrosome and lots of mitochondria

169
Q

Squamous epithelium

A

Epithelium which is only one cell thick and specialised for rapid diffusion

170
Q

Stem cell

A

Typed of undifferentiated cell which has ability to divide many times and differentiate into many different cell types

171
Q

Stomata

A

Small openings in the leaves or stem of a plant that can be opened or closed by guard cells in response to varying conditions

172
Q

Telophase

A

Final stage of mitosis where new nuclear envelopes begin to form around the separated sets of chromosomes

173
Q

Telophase 1

A

4th stage of meiosis where nuclear envelopes reform around the separated chromosomes and they uncoil

174
Q

Tissue

A

Group of specialised cells working together to carry out a specific function

175
Q

Totipotent stem cell

A

Stem cell which can differentiate into any cell in body/placenta

176
Q

Xylem

A

Tissue in plants specialised for water transport and dissolved minerals up plant

177
Q

Name of covalent bond between two adjacent amino acids in chain of amino acids

A

Peptide bond

178
Q

Type of reaction to break a peptide bond and what happens

A

Hydrolysis

Water is added

179
Q

How does an enzyme e.g. Pepsin break down a substrate

A

The substrate shape is nearly complementary to active site

Substrate enters active site on enzyme

Induced fit forms an ESC

Straining of bonds in substrate forms EPC

Products leave active site

180
Q

Pepstatin acts as a competitive inhibitor of pepsin, what can we conclude about the structure

A

Similar shape to substrate

Complementary to part of active site

181
Q

Describe how to do an emulsion test for lipids and how a positive result is identified

A

Mix with ethanol and water and it will go cloudy

182
Q

How might the lipid content of a mycoprotien differ from food that comes from animals

A

Has less overall lipid
Less saturated fat/lipid

183
Q

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

A

Is a medium for metabolic reactions because it allows ionic compounds to separate

Organisms can absorb minerals and food

184
Q

Property of collagen which makes it a useful component of blood vessel walls

A

Strength

185
Q

Structure of a collagen molecule

A

Peptide bonds between amino acids in a polypeptide
Every 3rd amino acid is the same
Coil in a spiral

Three polypeptide chains

H binds between polypeptide chains

No/few hydrophilic r groups on outside of molecule

186
Q

Function of Hb

A

Transport of 02

187
Q

How does structure of Hb differ to collagen

A

Haemoglobin is globular, has 4 polypeptide chains and has hydrophonic r groups on inside and hydrophilic on outside

188
Q

How is a peptide bond formed

A

Between amine group and carboxyl group of another
Through a condensation reaction

189
Q

Ways that physical properties of water allow organisms to survive over a range of temperatures

A

High latent heat of vapourisation
Evaporation is efficient cooling mechanism
Example of a cooling in living organisms

High SHC

Thermally stable environment for aquatic organisms
Aquatic organism use less energy in temp control
Bio reactions function correctly

Ice less dense than wardr
Ice is a habitat

190
Q

Roles of cholesterol in living organism

A

Fluidity of phospholipid bilayer

Making bile salts

191
Q

Describe different ways LDLs and HDLs effect formation of atheromas

A

LDL
Carry cholesterol from liver to tissue, receptors on tissue cells
Raises blood cholesterol
Increases deposition of fats in artery wall

HDL
Carry cholesterol from tissue to liver
Receptors in hepatocytes
Lowers blood cholesterol
Reduce deposition of fats

192
Q

Why are diets with high red meat content associated with high blood cholesterol

A

Red meat contains lots of saturated fat
Saturated fat associated with increase amounts of LDLS

193
Q

Why does glycogen make a good storage molecule

A

It’s insoluble so doesn’t effect water potential of cell

Lots of branches for enzyme to attach

Compact

194
Q

Structure of Hb molecule

A

Chain of amino acids joined by peptide bonds

Alpha helix, small regions of beta pleated sheets, hydrogen bonds

Hydrophilic r groups outside and hydrophonic o inside

4 polypeptide 2 alpha chain 2 beta

1 Haem group per polypeptide

Prosthetic group is Haem

195
Q

Structure of triglyceride molecule

A

One glycerol and 3 fatty acids and ester bonds

196
Q

Three roles of lipids in living organism

A

Thermal insulation

Membranes control entry and exit into cells

Waterproofing

197
Q

What is the role of mRNA

A

Carries genetic information out of nucleus and transfers it to the ribosome for protein synthesis

198
Q

Why are different enzyme involved in different stages of digestive processes

A

Enzymes are specific as substrates different shapes

Active site and substrate are complimentary for Lock and Key

199
Q

What is the difference between globular and fibrous proteins

A

Globular:
Ball shaped, forms H binds with water, soluble
Hb carries o2
Contains prosthetic group

Fibrous:
Long chain form H binds with adjacent chains
Insoluble
Collagen firms cross links with molecules
Part of cartilage

200
Q

How does a nucleotide base sequence in a gene synthesise a polypeptide

A

Transcription
-DNA transcribed in mRNA
-Activated RNA nucleotides line up by complementary base pairing to one template strand
-Catalyses by RNA polymerase

Translation
-mRNA moves to ribosomes
-tRNA molecules bind to mRNA
-anticodons match with codons
-specific amino acid attached to tTRNA
-formation of peptide bind between amino acids

201
Q

Suggest why DEG-contaminated wines with a high ethanol content may result in less
DEG poisoning than contaminated wines with a low ethanol content.

A

Ethanol competes with DEG
When at a higher conc ethanol is more likely to collide with active site

Less DEG broken down

202
Q

How might structures of enzymes of antartica and non antarctic fish differ

A

Different amino acid sequences

Different secondary structure

203
Q

Explain the effect of increasing the concentration of substrate on the rate of reaction;
(i) without inhibitor

A

More substrate molecules enter active site
More ESC’s formed
At low conc not all active sites occupied
At a higher conc- max turnover rate

204
Q
A

OCR A level bio (10 decks)

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