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Flashcards by charlottetoyne23, updated more than 1 year ago
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| Question | Answer |
| what is the maximum resolution and maximum magnification of the light microscope and the electron microscope? | Resolution: light=200nm electron microscope=0.20nm Magnification: light=*1500 TEM=*500,000 SEM=*100,000 |
| actual size= Magnification= | Actual size= image size --------------------- magnification Magnification=image size ---------------------- actual size |
| define resolution and magnification? | Resolution= the ability to distinguish between 2 separate points clearly. Magnification=The state of something being magnified or represented by an amplified image. |
| outline the roles of the cytoskeleton? | -keeps the cells shape -allows movement of organelles -supports the cell |
| role and structure of vesicles? | -membrane bound sacs found in cells - transport many different materials around the cell |
| structure and role of nucleus? | Structure:-surrounded by nuclear envelope -nuclear pores in nuc envelope. -nucleolus in the nucleus -has chromatin Role: -houses genetic info -contains chromatin that condenses during mitosis. -nucleolus makes RNA and ribosomes. |
| structure of RER? | -flattened sacs called cisternae. -joined to the outer nuclear memb. -littered with ribosomes that make proteins. |
| structure and role of SER? | Structure-same as RER without ribosomes role:-involved in making lipids that the cell needs |
| structure and role of Golgi? | structure: flat memb bound sacs role: receives proteins from the ER and modifies them by possibly adding a sugar mol. then packages the modified proteins into vesicles that can be transported. some modded proteins go to the cell surface to be secreted out. |
| structure and role of mitochondria? | structure: 2 membranes separated by fluid filled space. inner membrane is highly folded to form cristae. central part is called matrix. role: produces the energy that drives the cells (ATP) |
| structure and role of chloroplasts? | structure: 2 memb separated by fluid filled space. inner memb is continuous, with elaborate network of flattened memb sacs called thylakoids. a stack of thylakoids are called granum/grana. role: site of photosynthesis, light energy used to drive reactions of photosynthesis, carbohydrate mol are made from carbon dioxide and water. -found on thylakoid memb and in intergranal memb. |
| structure and role of lysosomes? | structure: single memb, spherical sacs. role: contain powerful digestive enzymes. used to break down pathogens ect. |
| structure and role of ribosomes? | structure: some are free in cell and some bound to RER. role: site of protein synthesis, act as assembly line where coded info from mRNA is used to assemble proteins from amino acids. |
| structure and role of centrioles? | structure: small tubes of protein fibres. pair of them next to the nucleus. role: take part in cell devision, form fibres known as spindle fibres that move chromosomes during nuclear division (anaphase) |
| outline the process of protein synthesis | -DNA is part of larger structures (chromosomes), which are unable to move from the nucleus, intermediate messenger molecules are needed. These are messenger RNA molecules. -The completed mRNA molecule detaches from the DNA template and exits the nucleus via the nuclear pores, moving into the cytoplasm. -The mRNA is now ready for translation, which is organised by the ribosomes, which now attach themselves to the mRNA. -the assembled protein leaves the ribosome by pinching off in a vesicle , it may leave the cell or be used in the cell. |
| outline roles of membranes | -separating cell contents from the outside environment -separating the cell components from cytoplasm. -cell recognition and signalling. -holding the components of some metabolic pathways in place. -regulating the transport of materials into or out of the cell. |
| outline the structure of a phospholipid membrane | -hydrophilic head (water loving) -hydrophobic tails (water hating) face inwards. -cholesterol maintains the fluidity of the membrane. -channel proteins allow the movement of some molecules through the membrane. -carrier proteins actively move substances across the memb. -glycoproteins/glycolipids: receptor sites. |
| define cell signalling? | the communication between cells using a hormone and a complimentary receptor site that will bring about a change in other cells. |
| define diffusion? Define active transport | diffusion is the movement of molecules down a concentration gradient. (from an are of high concentration to an area of low) active transport is the movement of molecules against its concentration gradient with the use of an energy source such as Adenosine tri-phosphate (ATP) |
| what effects the rate of diffusion? | -temperature -concentration gradient -distance -size of molecules -movement/stirring -surface area |
| outline facilitated diffusion using channel proteins -give an example outline facilitated diffusion using carrier proteins -give an example | facilitated diffusion is a passive process, (requires no energy). allows the transport of ions such as sodium and calcium ions.facilitated carrier-diffusion is a passive process, (requires no energy). -larger molecules such as glucose and amino acids. |
| what are the passive and active processes? | Passive:-diffusion -facilitated diffusion -osmosis Active:-active transport -bulk transport (-endocytosis (coming into the cell) -exocytosis (leaving the cell) -requires ATP ) |
| define osmosis? | -The movement of water down its water potential gradient. (the same process as diffusion just with water travelling from an area of high conc to an area of low concentration. -Across a partially permeable membrane. |
| what happens to animal cells in a solution with high water potential? | -solution has high water potential. - the cell has a lower water potential. -osmosis (diffusion of water down the water potential gradient) -cell swells as water moves down the gradient and fills the cell. -the ANIMAL cell bursts as it does not have a cell wall like a plant cell to withstand the pressure. |
| what happens to plant cells in a solution with high water potential? | -solution has high water potential. - the cell has a lower water potential. -osmosis (diffusion of water down the water potential gradient) -cell swells as water moves down the gradient and fills the cell. -the PLANT cell becomes turgid (filled with water). -plant cells have a cell wall that prevents the cell from bursting. osmosis will stop even if there is still a water potential gradient between the cell and solution. |
| what happens to animal cells in a solution with a low water potential? | - solution has lower water potential than the cell. -gradient from inside of cell to the outside. -water leaves cell by osmosis to fill this gradient. -the cell will shrine, contents will shrink and the membrane will shrivel up. |
| what happens to plant cells in a solution with low water potential? | - solution has lower water potential than the cell. -gradient from inside of cell to the outside. -water leaves cell by osmosis to fill this gradient. -the cell will shrink, as it loses water. -cell surface membrane will pull away from cell wall (plasmolysis) |
| outline the phases of mitosis | -interphase: cell goes about daily activities (growth and development) prophase: replicated chromosomes supercoil (shorten and thicken) metaphase: replicated chromosomes line up down the centre of cell. anaphase: replicase of each chromosome are pulled apart by spindle to opposite poles of cell. telophase: two new nuclie form. |
| define diploid and haploid cell | Diploid-containing two complete sets of chromosomes, one from each parent Haploid-A haploid cell is a cell that contains one complete set of chromosomes. |
| role of RER? | -translates the mRNA that codes for amino acids These secretory proteins (enzymes) are manufactured here. The term secretory just means that these proteins are made for secretion, or delivery outside the cell, into the body. -Once a protein has been synthesized (made), Rough ER creates a bubble around it by pinching off a portion of its own membrane. This bubble is called a “transition vesicle.” The transition vesicle then moves either to the cell membrane or to the Golgi Apparatus. |
| what prevents plant cells from dividing like mammal cells? What are the only plant cells that are arble to divide | they have developed a cell wall making the splitting near impossible for the cell. meristem cells have very thin walls. Meristem |
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