T1 - cell structure Flashcards
What are the main characteristics of aeukaryotic organism?
A eukaryotic organism is an organism whose cells containmembrane-bound organelles, e.g. a nucleus and mitochondria.
True or False? Prokaryotic organisms contain a nucleus.
False. Prokaryotic organisms donotcontain a nucleus.
What is aprokaryotic organism?
A prokaryotic organism is an organism whose cellslack a nucleusand othermembrane-bound organelles.
True or False? All prokaryotic organisms aresingle-celled.
True. Prokaryotic organisms are always single-celled.
Define the termplasmid.
A plasmid is a small circularloop of DNAfound inprokaryotic cells.
True or False? Eukaryotic cells arelargerthan prokaryotic cells.
True, eukaryotic cells are larger than prokaryotic cells.
Eukaryotic cells are typically between 10 and 100 µm. Prokaryotic cells are much smaller in comparison to eukaryotic cells, with many measuring ~ 1 µm in size.
How manymicrometres(µm) are in amillimetre(mm)?
There are 1000 µm in 1 mm
There are 1,000,000 nanometres in a millimetre, what is 1,000,000 instandard form?
1,000,000 in standard form is1 x 106
True or False? To convert a measurement fromnanometrestomicrometresyou must multiply by 1000.
False, to convert a measurement from nanometres to micrometres you mustdivideby 1000
If a eukaryotic cell is100µmwide and prokaryotic cell is1µmwide, how much bigger is the eukaryotic cell in terms oforders of magnitude?
The eukaryotic cell is2 orders of magnitude widerthan the prokaryotic cell
1 = 100and 100 = 102, therefore it is2orders of magnitude wider
Whatseparatescells from their surrounding environment?
Thecell membraneseparatescells from their surrounding environment.
Name thelargest organellepresent within animal cells.
The largest organelle within animal cells is thenucleus.
Name the structurespresent in plant cellsthat arenotpresent in animal cells.
Cell wall, Chloroplasts, Permanent vacuole
True or False? Ribosomesare present in both plant and animal cells.
True. Ribosomes arepresent in plant and animal cells. They are the site of protein synthesis.
Namethree organellesfoundwithinanimal cells.
Nucleus, Mitochondria, Ribosomes
(the cell membrane and cytoplasm arenotorganelles, so are not acceptable answers here)
What is thesmallest organellepresent in both plant and animal cells?
Ribosomesare the smallest organelle; they are present in both plant and animal cells.
True or False? Thegel-like fluidpresent inside both plant and animal cells is the chloroplast.
False. The gel-like fluid present in plant and animal cells is thecytoplasm.Chloroplastsare organelles found in plant cells.
True or False? The role of thenucleusis to release energy for the cell.
False. The role of the nucleus is tostore genetic informationin the form ofDNA. Energy is released by themitochondria.
What is the function ofchloroplastswithin plant cells?
Chloroplastsabsorb light energyduring the process ofphotosynthesis.
True or False? Plant cell wallsare responsible for controlling the passage of substances in and out of cells.
False. Plant cell walls providestrengthand additionalstructural supportfor plant cells. It is themembranethat regulates the passage of substances.
What is the function of thepermanent vacuolein plant cells?
The permanent vacuolestorescell sapand providesstructural supportfor plant cells.
True or False? Mitochondriaare the site of aerobic respiration.
True. Mitochondria are responsible forreleasing energythrough the process ofaerobic respiration.
Define the termspecialised cell.
Specialised cells are cells that have developedspecific characteristicsthat allow them to performparticular functions.
Give an example of aspecialised plant cell.
root hair cell, palisade mesophyll cell, xylem and phloem cells
Give an example of aspecialised animal cell.
red blood cells, nerve cells, sperm / egg cells, muscle cells
True or False? Root hair cells have an increased surface area.
True. Root hair cells have anincreased surface areato allowincreased absorptionof water and mineral ions from the soil.
What is thefunctionof anerve cell?
The function of a nerve cell is toconductelectricalimpulsesand send signals around the body.
True or False? An adaptation of a muscle cell is that they contain a lot of mitochondria.
True. Muscle cells contain a lot of mitochondria to carry out aerobic respiration andprovide energyfor muscle contraction.
True or False? Sperm cells contain a full set of chromosomes (46) from the father.
False. Sperm cells containhalf the amount of DNAcontained to normal body cells.
Why areroot hair cellsadapted to contain alarge number of mitochondria?
Root hair cells contain a lot of mitochondria to provide energy for theactive transport of mineral ions from the soil into the cell.
What is the function of aphloemcell?
Phloem cells form a long vessel to allow the plant totransport dissolved sugars and amino acids.
True or False? Phloem vesselsare strengthened and supported by a substance calledlignin strengtheningthe tubes and providingsupportfor the plant.
False. Xylem vesselsare supported by lignin.
What iscell differentiation?
Cell differentiation is the process by which a cell changes to becomespecialised.
True or False? Almost all cells in a multicellular organism containdifferentgenetic information.
False. Almost all cells in a multicellular organism contain thesamegenetic information.
Whatdetermines the featuresof specialised cells?
The features of specialised cells are determined by theexpression of genesin the nucleus.
True or False? Allplant cellsdifferentiateearlyin development.
False. Many types of plant cellsretainthe ability to differentiatethroughoutlife.
When doesmostcell differentiation occur inanimals?
In animals most cell differentiation take place during theearly stages of developmentwhen the animal is an embryo/fetus (before it is born).
What is alight microscope?
A light microscope is an instrument that uses light and lenses to magnify specimens, allowing visualisation of cells and large subcellular structures.
What doesresolutionmean in microscopy?
Resolution in microscopy means the ability todistinguish between two closely spaced objects as separate entities.
What is anelectron microscope?
An electron microscope is an instrument that useselectron beamsinstead of light to provide muchhigher resolution and magnificationthan light microscopes.
True or False? Electron microscopes use light beams for imaging.
False. Electron microscopes use electron beams for imaging.
True or False? Upon the invention of the light microscope in the 17th century, scientists were able to view cell structure in detail.
False. The first light microscopes to be invented allowed only very basic details of cell structure to be observed, such as cell shape and the plant cell walls.
What is the formula forcalculating magnification?
magnification = image size ÷ actual size
True or False? Magnification has units.
False. Magnification doesnothave any units and is just written as, e.g. x10 or 5000x.
What is the equation for calculating theactual sizeof a specimen?
actual size = image size ÷ magnification
What is the purpose of amagnification scalein microscope drawings?
A magnification scale is included to show theactual sizeof the observed specimen.
What is a microscopeslide?
A microscope slide is athin, flat piece of glasson which specimens are prepared for observation under a microscope.
Whatstainis used forcheek cells?
Methylene blueis used to stain cheek cells.
True or False? Iodine is used to stain onion cells.
True. Iodine is used to stain onion cells.
What should beavoidedwhen preparing a microscope slide?
Smudgingthe glass slide andtrapping air bubblesunder the coverslip should be avoided when preparing a microscope slide.
What is anobjective lens?
An objective lens is the lens on a microscope that isclosest to the specimen. Most light microscopes have several objective lenses at different powers for viewing specimens at different levels of magnification.
True or False? The highest-powered objective lens should always be used first when viewing a specimen under a light microscope.
False. When viewing a specimen under a light microscope thelow-power lens should always be used first.
What are the key characteristics ofbiological drawings?
use a sharp pencil; pencil lines should beclearandunbroken; all structures drawn should be inproportion; identifiable features must belabelledusing straight, uncrossed lines
How largeshould biological drawings be?
Biological drawings should take upat least half of the space availableon the page
Define the termbinary fission.
Binary fission is a type of simplecell divisionby whichbacteriamultiply.
What happens to thenumber of bacterial cellsafter a binary fission event?
The number of bacterial cellsincreases by a power of 2 (doubles)each time binary fission occurs.
What isaseptic technique?
Aseptic technique is a method used toprevent contamination by unwanted microorganismswhen working with cultures.
True or False? Lifting the lid of a petri dish only slightly when transferring bacterial cultures is primarily to prevent air from entering.
False. Lifting the lid of a petri dish only slightly primarilyreduces the risk of contamination by other microorganisms.
Why should theinoculating loop be passed through a hot flamebefore it is used to transfer bacteria to a culture medium?
The inoculating loop should be passed through a hot flame to kill any microorganisms present on the loop; thisprevents contamination.
Why should the lid of the petri dish besecured with tapeat intervals around the dish, rather than all the way around?
The lid should be secured with tape at intervals, rather than all the way around, to ensure thatoxygen can enterthe dish; this prevents the growth of anaerobic bacteria which may be harmful.
What is thehighest incubation temperaturefor growing bacteria in a school laband why?
The maximum allowed temperature for growing bacteria in a school lab is25°C, this is torestrict the growth of harmful pathogens.
What is aninhibition zonein the context of culturing microorganisms?
An inhibition zone is anarea around a disc of antibiotic, antiseptic, or disinfectant wherebacterial growth is inhibited.
What is theequationfor calculating the area of aninhibition zone?
Area of inhibition zone = πr2, Where π = 3.14 and r = the radius of the zone of inhibition
What is themean division timeof bacteria?
Mean division time is theaverage length of timethat it takes for abacterial cell in a population to divide.
True or False? Alarge zone of inhibitionindicates that theantibiotic is effectiveat killing the bacteria.
True. The bigger the zone of inhibition, the more effective the antibiotic is at killing the bacteria.
What is indicated bythe absence of a zone of inhibitionaround an antibiotic disc?
If there is no zone of inhibition it indicates that the bacteria isresistantto a particular antibiotic.
When investigating the effect of antibiotics on bacterial growth using agar plates and zones of inhibition, what should be used as anexperimental control?
When investigating the effect of antibiotics on bacterial growth using agar plates and zones of inhibition the control should bepaper discs soaked in sterile water.
How canmicroorganisms be culturedfor use in an investigation?
Bacteria can be cultured in anutrient broth solutionor ascolonieson an agar gel plate.
