Flashcards
Cell Structure, Microscopy and Cell Fractionation
Flashcards do conjunto (62)
- 1What is the cell theory?All living cells are made up of cells.
- 2Define unicellular.An organism made up of one cell only.
- 3Define multicellular.An organism made up of many cells.
- 4What does specialised mean and give examples.A specialised cell is a cell that has adaptations which allow it to carry out its specific function. E.g. red blood cells, lymphocytes, etc.
- 5Define prokaryotic cell.A cell without a nucleus, and they have much simpler structures without membrane bound organelles.
- 6Define eukaryotic cells.Cells that have a nucleus bound by a membrane and complex membrane bound organelles.
- 7Describe the structure of the cell membrane.- It is a double membrane.
- Made up of two layers of phospholipids/ phospholipid bilayer.
- It is embedded with proteins. - 8What is the function of the cell membrane.- Controls the entry and exist of substances in and out of the cell.
- Helps maintain different conditions on either side of the cell. - 9Difference between plasma membrane and the cell membrane.- Plasma membrane is found around organelles, cell membrane is found around the cell.
- 10Describe the structure of the nucleus.- Large and round in shape.
- Has a dark staining region called the nucleolus.
- They have a double membrane called the nuclear envelope.
- Nuclear envelope has pores which allows the exchange of substances between the cytoplasm and the nucleus. - 11What is the function of the nucleus?- It contains protein bound linear DNA. DNA holds all of the genetic information needed to control the activities of the cell.
- 12what is the function of the nucleolus?- These produce ribosomes.
- Also produces ribosomal RNA - 13Describe the structure of the mitochondria.1. They have a double membrane - their inner membrane is folded into a cristae - this increases the surface area for respiratory enzymes.
2. They have an oval shape.
3. Have a matrix. - 14what is the function of the mitochondria?- site of aerobic respiration.
- They respire aerobically to produce ATP which releases energy. - 15What are lysosomes ?- A type of golgi vesciles
- speherical organ and it contains hydrolytic/ digestive enzymes called lysozymes within a single membrane. - 16What is the function of the lysosomes?- They digest protein molecules and other structures inside the cell.
- 17What is the structure of ribosomes.- Made up of two subunits of proteins and Ribosomal RNA rRNA.
- They have no membrane
- Usually attached to the rough ER. - 18What is the function of ribosomes?Site of protein synthesis, from amino acids by condensation reaction, releasing a water moelcule and forming a peptide bond.
- 19Describe the structure of the endoplasmic reticulum.- These membranes that form a series of tubes in the cytoplasm of the cell.
- They can originate from the nucleus. - 20What are the 2 types of ER?1. Rough ER.
2. Smooth ER. - 21What is the function of the rough ER?1. Provide a larger surface area for the synthesis of proteins.
2. provide a pathway for transport of substances espically proteins in the cell. - 22What is the function of smooth ER?1. Synthesis of lipids.
2. Transport of lipids.
3. Synthesis and transport of carbohydrates, - 23What is the structure of the golgi apparatus?It is a stack of flattened sacs each surrounded by a membrane.
vesicles are continuusly being pinched off the ends of the sacs. - 24What is the function of the golgi apparatus?- It packages and processes molecules such as proteins.
Also forms lysosomes, glycoproteins, etc. - 25What is the structure of microvilli?Tiny finger like projections of the cell surface membrane.
- 26What is the function of the microvilli?- increase the surface area to maximise the rate of absoption.
- 27Describe the structure of the cell wall.- Thin layer made from cellulose found outside the cell surface membrane.
- 28Function of the cell wall.- Provides strength and support.
- Stops cell from bursting when it is in a dilute solution by preventing cell from bursting. - 29What is the function of the middle lamella?It marks the boundary between the neighbouring cell walls in plant cells.
- 30Describe the structure of chloroplasts.1. Grana - a stack of round 100 thylakoids.
2. Thylakoid - contain the pigment chlorophyll which absrob light for photosynthesis They have disc shape structures.
3. Stroma - fluid filled matrix.
Also have a double plasma membrane. - 31Which 2 cells contain chloroplasts?1. plant
2. Algal. - 32function of the chloroplastsPhotosynthesis.
- 33What is the vacuole?A sac filled with fluid surrounded by a membrane called the tonoplast. Found in plant cells' cytoplasm.
The fluid inside is called cell sap and it is water dissolceved in other substances. - 34Function of the vacuole.1. Keep plant cells turgid.
2. Amino acids and sugars act as a temp food store.
3. pogments may colour petals and attract pollinating insects. - 35Give examples of eukayotic cells.1. Fungi
2. Algae
3. Plant cells.
4. Animal cells. - 36What does it mean for a cell to differentiate?The cell becomes speciliased?
- 37How do cells differentiate?By reading different parts of the same genetic material and ignoring the other parts.
- 38What are the 4 types of mammlian tissues?1. Nervous tissue.
2. Connective tissue
3. Muscular tissue
4. Epithelial tissue. - 39What are tissues, organs and organ systems?1. Tissues are a group of similar cells that have the same functions.
2. Organs are a group of tissues which work towards the same function.
3. Organ system are a group of organs which work together to carry out a specific physiological function. - 40What is the difference between eukatyotic cells and prokaryotic cells?1. prokayotic cells are smaller than eukryotic cells.
2. Prokayoritc cells do not have membrane bound organelles.
3. Prokyatoic cells do not have a true nucleus. - they have a single cirucular DNA strand free in the cytoplasm. (circular DNA)
4. Prokaytoic cells have smller ribosomes.
5. Prokyarotic cells have a murein cell wall.
6. pro have plasmids - tiny ciruclar loops of DNA
7. pro have flagellum- it propells it llowing it to move through fluids,
8. pro have capsules - those store toxins nd prevent bacterium from drying out and being attacked by white blood cells.
9. Pro have no nuclelous. - 41What are viruses?small simple structures.
- 42what are the 2 ways that viruses are described?1. acellular - they cannot reproduce outside host cells.
2. non liviing have no ode of metabolism. - 43describe the 3 main structures of viruses.1. genetic material which could be DNA or RNA. (HIV have RNA) BUT NOT BOTH.
2. attachment proteins
3. capsid / protein shell - 44gIVE 3 EXAMPLES OF VIRUSES.1. adenovirus
2. influenza virus
3. HIV
4. Polio - 45what is an object?the material put under a microscope.
- 46what is an image?the appearance of the material put under the microscope when viewed uder the microscope.
- 47what is magnification?This is how many times bigger / larger is the image is compared to the actual object/
- 48how is magnification calculated?image / actual size
- 49what is resolution?the minimum distance that two objects can be apart for them to appear as two seperate items.
- 50what does an electron microscope have a better resolution than 1 ligh microscope.- A beam of electrons will have a shorter wavelength than light.
- 51what does it mean to have a greater resolution.greater resolution = greater clarity = cleaer and more precise image.
- 52how to calculate the resolution.resolution = wavelength / 2
- 53what are the two types of microsocopes.1. light microscope / optical
2. electron - 54what are the 2 types of electron microscope.1. transmission electon microscope
2. scanning electron microscope. - 55which microsocpe gives a higher magnification? and better resoltuion.an electron microscope.
- 56hhow does a transmission electron microscope work ?This works by absorbing the elecrons tht pass through the organeles and so the desner organeles will absorb more electrons and appear darker. Electrons pass through the speimen.
- 57main advantages of using TEM instead of SEM.1. Higher magnification can be achieved with TEM
2. Better / higher reslutn can be achieved using TEM and so more detail of small structures / organellescan be seen. - 58disadvnatges of using TEM instead of SEM1. Long prep method.
2. Specimen is in a vacuum, cannot look at living materil
3.artefacts present
4. image is not in 3d
5. specimen must be very thin so electrons can pass through it. - 59how does a scanning electron microscope work?the electrons bounce off the structure,
- 60advantages of using SEM rather than TEM1. can view surface of specimen
2. image in 3D
3. thin sections do not need to be prepared. - 61How would we understand the function of the organelles?1. obtain a pure sample containing lots of the organelles you want to investigte,
2. sepeprate the organelles by cell fractionation. - 62Describe cell fractionation- a process in which the cells are broken up and the different organelles they contain are seperated out.
1. tissue is cut up and put in a cold isotonic buffered soltion.
- cold to reduce enzyne activity
- isotonic to prevent osmosis so prevent shrinkig and brusting of organelles.
- buffered to prevent damage to enzymes and maintain a constant pH.
2. The tissue is then placed in a homogeniser to release the organelles, the homogenate is removed a filteretd to remove complete cells and cel debris.
3. homognetae placed in an ultracentifuge and spun at high speed, first pellet/ thin sediment is nucleibcs most dense. then supernatant is removed and spun at a higher speed.
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- GCSE Biology (Generalo) FlashCards sobre Cell Structure, Microscopy and Cell Fractionation , criado por ray :) em 08-05-2017.
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