Cambridge A-Level Biology I: Cell Structure Exam Questions, Exams of Nursing

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Unit 1 Cell Structure I Primrose Kitten Exam

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ORGANELLE - Correct Answers ✅A specialised part of a cell that performs a particular function. MAGNIFICATION - Correct Answers ✅The ability of a lens to enlarge the size of an object. Calculated by dividing the image size by the real size of the object. RESOLUTION - Correct Answers ✅The ability of a microscope to distinguish two adjacent points as separate from each other. MICROMETER μm - Correct Answers ✅An SI unit of measurement which is one thousandth of a millimeter NANOMETER nm - Correct Answers ✅An SI unit of measurement which is one thousandth of a micrometre TRANSMISSION ELECTRON MICROSCOPE - Correct Answers ✅A beam of electrons focussed by electromagnets pass through ultra-thin dead tissue samples. Capable of a maximum magnification of x500 000 and a resolution of 0.2nm. SCANNING ELECTRON MICROSCOPE - Correct Answers ✅A focussed beam of electrons is passed across the surface of the specimen to

Unit 1 Cell Structure I Primrose Kitten Exam

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produce a three dimensional view of the surface. Maximum magnification is x100 000 and maximum resolution is 10nm. LASER SCANNING COFOCAL MICROSCOPE - Correct Answers ✅Based on a conventional optical microscopy and used to enhance optical resolution. Cells are stained with fluorescent dyes. A thick section of tissue or small living organism is scanned with a laser beam, which is reflected by the dyes to produce a computerised 3D image. EYE PIECE GRATICULE - Correct Answers ✅A circular disc fitted into the eyepiece of a microscope, which has a scale marked on it with equal divisions in arbitrary units. The length of each division varies as the objective lens is changed. STAGE MICROMETER - Correct Answers ✅This is used to calibrate the scale on the eye piece graticule for each objective lens used. The micrometre slide has a scale engraved into it, calibrated in known divisions e.g. 0.1mm. CALIBRATE - Correct Answers ✅To determine, rectify or mark the graduations of a measuring instrument. e.g. using a stage micrometre to determine the length of each division on an eye piece graticule.

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

reproductive hormones. (iii) synthesise, store and transport carbohydrates; (iv) detoxify lipid soluble drugs. GOLGI APPARATUS - Correct Answers ✅Consists of a series of unconnected flattened membranous sacs called cisternae and Golgi vesicles. The functions of the Golgi apparatus is to (i) modify proteins and lipids from the RER and prepare them for secretion. (ii) produce secretory enzymes (iii) form lysosomes CISTERNA - Correct Answers ✅Pleural is cisternae. A series of flattened tubular membranes found in the endoplasmic reticulum and Golgi apparatus. RIBOSOME - Correct Answers ✅A ribosome consists of a large and small subunit, containing ribonucleic acid [rRNA] and protein. Ribosomes are the site of protein synthesis and are located in the cytosol of eukaryotic and prokaryotic cells, as well as on RER in eukaryotic cells. Ribosomes in eukaryotic cells are larger and referred to 80s as opposed to 70s ribosomes in prokaryotes. MITOCHONDRION - Correct Answers ✅Mitochondria [pleural]. Double membrane bound organelle with its own DNA and 70S ribosomes, found in most eukaryotic cells. Site of aerobic respiration e.g. the Krebs cycle and oxidative phosphorylation.

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

CRISTAE - Correct Answers ✅Foldings in the inner mitochondrial membrane to provide a large surface area for the attachment of enzymes and other proteins involved in aerobic respiration. MATRIX - Correct Answers ✅The interior solution in the mitochondria. It contains lipids, and enzymes involved in the Krebs cycle. Mitochondrial DNA and 70S ribosomes allow the production of some mitochondrial proteins. CHLOROPLAST - Correct Answers ✅Double membrane bound organelle with its own DNA and 70S ribosomes, found in some plant cells. Photosynthesis occurs in this organelle. THYLAKOIDS - Correct Answers ✅A complex arrangement of internal membranes which are grouped into stacks called grana [singular: granum], joined by intergranal lamellae. Chlorophyll pigments which absorb light energy, are located on the thylakoid membranes. GRANUM - Correct Answers ✅A stack of thylakoid membranes, containing chlorophyll pigments which absorb light energy during cyclic and non cyclic photophosphorylation.

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

MICROTUBULES - Correct Answers ✅Microtubules are small tubular structures in the cytoplasm, composed of the polymer tubulin, a globular protein that is arranged in spirals. Microtubules form part of the cytoskeleton, which provides structure and support in eukaryotic cells. FLAGELLA - Correct Answers ✅Flagella [singular: flagellum] are composed of microtubules arranged in a ring of nine pairs surrounding two central microtubules. Flagella are found in some single cell organisms where they move the cell around e.g. Euglena; Chlamydomonas. A flagellum also forms the tail of motile sperm cells. CILIA - Correct Answers ✅Cilia [singular: cilium] are composed of microtubules arranged in a ring of nine pairs surrounding two central microtubules. Unlike flagella, cilia are shorter and are always present in large numbers on the surface of cells. Cilia play a role in the locomotion of protists such as Paramecium. Cilia move liquids across the surface of cells which is turn helps to remove contaminants such as mucus and bacteria in the respiratory tract; cilia play a role in the movement of the secondary oocyte in the oviduct towards the uterus. CELL WALL - Correct Answers ✅This is present in all plant cells and many members of the Protoctista and fungi. In plant cells, the cellulose cell wall consists of microfibrils made from chains of beta glucose

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

monomers, held together by 1,4 glycosidic bonds. Hydrogen bonds occur between adjacent chains. Bundles of microfibrils form fibres embedded in a matrix of pectins and hemicelluloses. The cellulose cell wall provides mechanical strength to prevent the cell from bursting when water enters the cell by osmosis. Collectively cellulose cell walls provide mechanical strength to the whole plant and as cellulose is fully permeable, it allows water to pass along it to enable the movement of water through the plant. The cell walls of fungi are made of a nitrogen containing polysaccharide called chitin. CYTOSKELETON - Correct Answers ✅Located within the cytoplasm and consists of microtubules and microfilaments. The cytoskeleton is responsible for (i) cellular movement using flagella and/or cilia; (ii) intracellular movement so that organelles can move from one part of the cell to another; (iii) supports organelles and provides a scaffolding that strengthens the cell. INTRACELLULAR - Correct Answers ✅Within a cell EXTRACELLULAR - Correct Answers ✅Within an organism but not inside cells e.g. tissue fluid; blood; lymph

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

PROKARYOTE - Correct Answers ✅Cells with no membrane bound nucleus or membrane organelles. Cell wall made of murein; circular DNA not associated with proteins; additional circular DNA plasmids may be present; ribosomes are smaller [70s]. Mucilaginous capsule may be present. CELL FRACTIONATION - Correct Answers ✅The process used to break up cells and isolate their different organelles to study their structure and function. HOMOGENATION - Correct Answers ✅The process used to break open cells to release the organelles from the cell. The process uses a blender/homogeniser and cold, isotonic buffered solution. ULTRACENTRIFUGATION - Correct Answers ✅Process which follows homogenisation. Fragments in the filtered homogenate are spun at different speeds in a centrifuge to separate different types of organelles from each other. TISSUE - Correct Answers ✅A collection of similar cells which perform a specific function e.g. epithelial tissue; xylem.

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

ORGAN - Correct Answers ✅A collection of tissues combined and coordinated together to perform a specific function e.g. heart; leaf; stomach. ORGAN SYSTEM - Correct Answers ✅A collection of organs which work together as a single unit, to perform specific functions more efficiently e.g. digestive system to digest and process food; respiratory system for breathing and gas exchange. VIRUS - Correct Answers ✅Non-cellular non-living particles which are smaller than bacteria, between 20-300nm. Consist of DNA or RNA enclosed within a protein coat called a capsid. MICROVILLI - Correct Answers ✅Finger like projections of the cell surface membrane, about 0.6μm in length. Often described as a 'brush border'. Used to increase the surface area of the cell surface membrane. CAPSID - Correct Answers ✅The protein shell of a virus which encloses its genetic material. A lipid envelop with embedded attachment proteins often surround the capsid in some viruses.

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

DIFFERENTIAL STAINING - Correct Answers ✅A stain which makes some cell structures appear darker or different in colour from other structures e.g. eosin is a permanent stain which stains cellulose red. CAPSOMERES - Correct Answers ✅Protein units which form the protein coat or capsid of a virus. The capsid protects the genetic material within it and may be surrounded by a lipid and protein membrane. GRAM STAIN - Correct Answers ✅A traditional method of classifying bacteria using a stain containing the chemical crystal violet. Gram staining splits bacteria into two types: Gram-positive and Gram- negative. GRAM NEGATIVE BACTERIA - Correct Answers ✅Stain pink with Gram stain. Peptidoglycan wall is thin and covered by a lipopolysaccharide layer. During Gram-staining, the crystal violet binds but the alcohol added later washes away the outer layer and the crystal violet is leached out. Counterstaining with safranin, results in the thin peptidoglycan layer becoming pink. GRAM POSITIVE BACTERIA - Correct Answers ✅Stain purple with Gram stain. Peptidoglycan wall is thick and takes up the crystal violet stain. The alcohol added later does not wash away the thick peptidoglycan

Unit 1 Cell Structure I Primrose Kitten Exam

Question & Answers 2025

layer and the purple stain remains. The counterstain, safranin has no effect on the violet colour. ATP [ADENOSINE TRI-PHOSPHATE] - Correct Answers ✅A nucleotide consisting of the nitrogenous base, adenine covalently bonded to the pentose sugar ribose, [so forming adenosine] and three phosphate groups forming a short chain. ATP is a compound that transfers energy within cells. It is the universal energy currency and used in metabolic processes, muscle contraction; active transport; exocytosis; activation of molecules. ADP [ADENOSINE DI-PHOSPHATE] - Correct Answers ✅A nucleotide consisting of the nitrogenous base, adenine covalently bonded to the pentose sugar ribose, [so forming adenosine] and two phosphate groups forming a short chain. ADP is formed from ATP during energy transfer in cells. The final phosphate group in ATP is removed by hydrolysis to release energy and inorganic phosphate. ATP SYNTHASE - Correct Answers ✅An enzyme which catalyses the conversion of ADP and inorganic phosphate into ATP. This is a condensation reaction as water is removed in the process. ATP HYDROLASE - Correct Answers ✅An enzyme which catalyses the conversion of ATP and water to ADP, inorganic phosphate and energy.