2A | Cell Structure and Division Flashcards

Question

What is the function of the Mitochondria?

Answer 1

The function of the mitochondria is to carry out respiration, where ATP is synthesized for generation of energy. Mitochondria is needed in cells which require a lot of energy.

Answer 2

Chloroplasts are small, flattened structures found in plant cells. They have a double membrane. Chloroplasts has membranes inside itself called thylakoid membranes - these membranes are stacked up in parts of the chloroplast to form grana. Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane.

Answer 3

They carry out photosynthesis. Some parts of photosynthesis happen in the thylakoid membranes (specifically the grana).

Answer 4

The Nucleus is a large organelle, consisting of a nuclear envelope and nucleolus. The Nucleus contains chromosomes which are protein bound linear DNA. The Nucleolus is a smaller part enclosed in the nuclear envelope. The nuclear envelope is a double membrane which contains many pores.

Answer 5

The Nucleolus is the area of the nucleus where ribosomes are made. The Nucleus is responsible for providing genetic information to the rest of the cell which gives the cell instructions on how to work, basically controlling the activities of the cell. The Nucleus has DNA, which contains instructions on how to create proteins. The Nuclear Envelope has pores which are holes in the double membrane which allows substances like RNA to move between the nucleus and the cytoplasm.

Answer 6

No, because they don't photosynthesize.

Answer 7

Cells, depending on their function, will need to be specialized. Specialization means that cells are able to do a function they are associated with better, so for example cells which produce mucus may need a lot of golgi and mitochondria in order to get the energy to release a lot of mucus at once.

Answer 8

Epithelial cells have villi to increase surface area so food can be absorbed at a faster rate into the cell. The cells on the surface of villi are called microvilli and are used to increase surface area even more for an even faster rate of absorbtion.

Answer 9

Cells become tissues by becoming a group of cells that perform a particular function. Different tissues work together to form organs. Different organs work together to form organ systems.

Answer 10

Ciliated cells have a lot of mitochondria. Mitochondria is the cell needed to generate energy which is done by aerobic respiration. Ciliated cells will have a lot of mitochondria because they need more energy.

Answer 11

Ribosome Rough Endoplasmic Reticulum Golgi Apparatus Golgi Vesicle

Answer 12

A flagellum is a long, hair-like structure. Not all prokaryotes have a flagellum, and some can have more than one.

Answer 13

The flagellum rotates in order to make the cell move.

Answer 14

``` Capsule Cell Membrane Cell Wall Ribosome Plasmid Flagellum ```

Answer 15

Flagellum Plasmid Capsule

Answer 16

Nucleus Mitochondria Chloroplast Vacuole

Answer 17

The capsule is an organelle on the surface of some prokaryotes, usually bacteria. It is made from secreted slime.

Answer 18

The capsule offers protection to the cell against the immune system.

Answer 19

The plasmid is a round, circular loop of DNA that isn't part of the main circular DNA molecule in a prokaryote. Prokaryotes can have variable numbers of plasmids, sometimes none.

Answer 20

The plasmid contains genes for things like antibiotic resistance and can be passed onto or between other prokaryotes.

Answer 21

DNA is stored in the nucleus in eukaryotes. DNA is stored in the cytoplasm in prokaryotes. DNA has histones to help it coil in eukaryotes. DNA does not have histones in prokaryotes, instead, it coils from a process called supercoiling.

Answer 22

'Acellular' means that the named does not consist of even one cell. 'Multicellular' means that the named is made of multiple cells. 'Unicellular' means that the named consists of only one cell.

Answer 23

Viruses are acellular. Prokaryotes are unicellular. Eukaryotes can be unicellular, but are usually multicellular.

Answer 24

A virus is an acellular particle made of amino acids and proteins. They are acellular, meaning they are not cells as they lack many of the biological functions needed, such as lacking ribosomes, cell membranes and cytoplasm.

Answer 25

Ribosome Cell Membrane Cytoplasm

Answer 26

Viruses have a protein coat around them, called a capsid. The capsid has small projections called attachment proteins which are used to cling onto host cells. Inside the virus, there is a core of genetic material which can either be DNA or RNA.

Answer 27

Binary fission is the process in which prokaryotes replicate. Before binary fission occurs, the prokaryotic cell replicates its genetic material. During this process, a variable number of plasmids can be made, not just double. After this, the cell gets slightly larger and DNA loops move to the opposite sides of the cell. Plasmids do not need to be equally spread throughout, but the two pieces of circular DNA must be on opposite sides of the cell. The cytoplasm begins to divide from the middle and new cell walls begin to form. The cytoplasm divides, and two daughter cells are produced. Each daughter cell has one copy of the circular DNA, but can have variable number of plasmid copies.

Answer 28

Viruses replicate by using their attachment proteins to bind to complementary receptor proteins on the surface of host cells. Different viruses have different attachment proteins and therefore require different receptor proteins on host cells. As a result, some viruses can only affect one type of cell. After the virus has attached to the complementary host cell's proteins on the cell surface membrane, it can inject it's genetic information into the host cell.

Answer 29

Firstly, the virus will bind onto the host cell using it's attachment proteins. The virus will then inject it's genetic information into the host cell. In that host cell, the new genetic information is kept separate from the cellular DNA. In the Lytic cycle, The new genetic information will instantly command the cell to reassemble and assemble new viruses by using the cell's own machinery. After there are many new viruses, there will eventually be so many of them that the host cell literally bursts because it can't hold them in - this is called lysis. This results in the release of many new viruses that will go to invade other host cells.

Answer 30

Firstly, the virus will bind onto the host cell using it's attachment proteins. The virus will then inject it's genetic information into the cell. In the Lysogenic cycle, the genetic information integrates into the DNA of the cell and stays dormant. Whenever the cell replicates by mitosis, the genetic information of the virus is carried over. Eventually, the genetic information of the virus will eventually not become dormant and all the host cells infected with the viral RNA/DNA will enter the lytic cycle, causing them all to burst at once and creating many new copies of viruses.

Answer 31

Attachment proteins

Answer 32

Genetic information (RNA or DNA)

Answer 33

Murein Firstly, the vibrio cholerae will replicate it's genetic information. Plasmids can be replicated to create variable amounts, but circular DNA only replicates once to create two copies. The prokaryote expands and the circular DNA strands move to opposite sides of the cell - plasmids don't spread out equally. A cell wall is then formed down in the middle as the cytoplasm begins to divide. After the cytoplasm has divided, you now have 2 cells with circular DNA and a variable number of plasmids. The strain of Vibrio cholerae that has a capsule allows it to have extra protection against the immune system.

Answer 34

Magnification is how much bigger the image is than the specimen. Resolution is how detailed the image is. More specifically, it's how well a microscope distinguishes between two points that are close together.

Answer 35

The formula for magnification is: size of the image ÷ size of the real object

Answer 36

5 ÷ 0.05 = x 100

Answer 37

x 1500 and 0.2μm.

Answer 38

Uses electrons to form an image Has more detail than the optical microscope, as the maximum resolution for an electron microscope is 0.002μm. The maximum magnification of an electron microscope is x 1,500,000. Using electron microscopes allows you to see the internal structures of organelles depending on the type of electron microscope used. Please note that to use an electron microscope the cell must be dead as a vaccum must be established inside the electron microscope in order for electrons to pass through it. This makes electron microscopes much more expensive and laborious to use.

Answer 39

TEMs use electromagnets to focus a beam of electrons which is transmitted through the specimen, so the specimen must be thin so there is a penetration. Denser parts of the specimen will absorb more electrons, making the denser area darker. With TEMs, you can see the internal structure of organelles which is extremely useful as you cannot with SEMs or optical microscopes.

Answer 40

Good things: The TEM has the maximum resolution of 0.002μm. This is the highest of an electron microscope and allows cells internal structure to be viewed in very high detail. The TEM has a much higher useful magnification than the SEM meaning more organelles can be seen in detail. Bad things: Specimen must be thin as electrons must penetrate it. The image generated is 2D.

Answer 41

SEMs do not penetrate the specimen, instead, a beam of electrons is scanned across the specimen which forms an image. The images you end up with show the surface of the specimen and they can be 3-D, as well as having color.

Answer 42

Good things: SEMs form a 3-D image, giving people a more clear understanding of organelles when looking into surface area, etc. SEMs give color, meaning organelles are easier to identify and gives more information on a certain organelle. Bad things: SEMs have a lower magnification and resolution than the TEM. SEMs cannot be used to view the internal structure of organelles, only the surface.

Answer 43

Here's how you prepare a 'temporary mount' of specimen on a slide: Star by pipetting a small drop of water onto the slide (a slide is a strip of clear glass or plastic), then use tweezers to place a thin section of your specimen on top of the water drop. Add a drop of stain. Stains are used to highlight objects in a cell, for example iodine in potassium iodide is used for starch grains. Finally, add the cover slip (a square of clear plastic that protects the specimen). To do so, stand the slip upright onto the slide next to the water droplet. Then carefully tilt and lower it so it covers the specimen. Try not to get any air bubbles under it as it may destruct the view of the specimen under the microscope.

Answer 44

Artefacts are things that you see on a microscope but aren't part of the actual cell or specimen that you're looking at. These could be water bubbles or some particles of dust.

Answer 45

Firstly, cut 1cm from the tip of a growing root, usually from an onion. It must be from the tip as that will be where the root is actively growing the most as it extends, so you will see most mitotic activity there. Then, after cutting, put the cut root into a boiling tube of hydrochloric acid and keep it there for 5 minutes. The boiling tube must be at 60°C. After that, drain the hydrochloric acid out of the boiling tube, then take your root tip and make sure it is rinsed out with cold water from a pipette. Leave the tip to dry on a paper towel. Then, place the tip on a microscope slide and cut 2mm from the very tip of it. Get rid of the rest. Use a mounted needle to break the tip open and spread the cells out thinly. Add a few drops of stain and leave it for a few minutes, it must be toluidine blue. Place a cover slip over the cells and push down firmly to squash the tissue. This will make the tissue thinner and allow light to pass through it. Don't smear the cover slip sideways as that will damage chromosomes. Now you can look at all the stages of mitosis under the optical microscope.

Answer 46

'Calibrate' the eyepiece graticule to the stage micrometer by lining the eyepiece graticule to one of the divisions on the stage micrometer so they are parallel. You must know one division on the stage micrometer is 0.1mm. Count up the amount of divisions in the eyepiece graticule that's needed in order to get to the next division on the stage micrometer. For example, depending on the magnification, you may need 3 divisions on the eyepiece graticule for 1 division on the stage micrometer.

Answer 47

One division on stage micrometer = 0.1mm Five divisions on eyepiece graticule = 0.1 0.1 ÷ 5 = 0.02 One division of the eyepiece graticule is equal to 0.02mm.

Answer 48

``` 1 m = 100 cm 1 m = 1000 mm 1 cm = 10 mm 1 mm = 1000 µm 1 µm = 1000 nm 100 nm = 0.1 µm ``` 1m = 1000mm 1mm = 1000µm 100 * 10,000 = 1,000,000

Answer 49

Clip the slide you've prepared onto the stage. Select the lowest powered objective lens (the lens on your microscope that produces the lowest magnification). Use the coarse adjustment knob to bring the stage up to just below the objective lens. Look down the eyepiece, and as you're looking, use the coarse adjustment knob to move the stage up and down until you reach a point where the specimen is roughly in focus. Adjust the focus with the fine adjustment knob until you get a clear image of what's on the slide. If you need to see a slide with a greater magnification, swap to a higher powered objective lens and refocus.

Answer 50

1 = Lowest and highest powered objective lens 2 = Microscope stage 3 = Light 4 = Fine Adjustment Knob 5 = Coarse Adjustment Knob 6 = Eyepiece

Answer 51

Genetically identical cells.

Answer 52

Gap phase 1 Synthesis Gap phase 2

Answer 53

The cell grows, with new organelles and proteins being made.

Answer 54

Cell replicates and unravels its DNA, ready to divide by mitosis.

Answer 55

Cell replicates it's organelles, with proteins necessary for cell division being made

Answer 56

Mitosis is needed for growth of multicellular organisms. Mitosis is also needed for the repair for damaged tissues.

Answer 57

Interphase

Answer 58

Interphase is a stage in the cell cycle before Mitosis. The cell carries out normal functions, but also prepares to divide. The cell's DNA is unraveled and replicated, in a stage called synthesis, to double its genetic content. The organelles are also replicated in gap phase 2, and proteins necessary for cell division are also synthesized in gap phase 2.

Answer 59

Prophase Metaphase Anaphase Telophase

Answer 60

Prophase is one of the four stages in Mitosis, where the cell begins its division process. Firstly, the chromosomes (each with two chromatids) condense, getting shorter and fatter. Tiny bundles of protein called centrioles start moving to opposite ends of the cell, forming a network of protein fibers across it called the spindle. The nuclear envelope breaks down and chromosomes lie free in the cytoplasm.

Answer 61

Metaphase is one of the four stages in Mitosis, where the cell begins its division process. The chromosomes (each with two chromatids) line up along the middle of the cell and become attached to the spindle by their centromere.

Answer 62

Anaphase is one of the four stages in Mitosis, where the cell begins its division process. The centromeres divide, separating each pair of sister chromatids. The spindles contract, pulling chromatids to opposite poles of the spindle, centromere first. This makes the chromatids appear v-shaped.

Answer 63

Telophase is one of the four stages in Mitosis, where the cell begins its division process. The chromatids reach the opposite poles on the spindle. They uncoil, becoming long and thin again and becoming chromosomes. A nuclear envelope forms around each group of chromosomes, so there are now two nuclei. The cytoplasm divides (cytokinesis) and there are now two daughter cells that are genetically identical to the original cell and each other. Mitosis is finished

Answer 64

Interphase This is because the nuclear envelope has not visibly dissolved yet.

Answer 65

Prophase This is because the chromosomes have condensed and the nuclear envelope has dissolved. It is not the other stages as you can see that the chromosomes have not been lined up or separated.

Answer 66

Metaphase You can see this as chromosomes are being visibly lined up along the middle of the cell, and have yet to be separated.

Answer 67

Anaphase This is because the sister chromatids have been separated by centrioles contracting on opposite poles of the cell, dividing the centromere, separating the sister chromatids from each other and going to opposite poles of the cell.

Answer 68

Telophase This is because the nuclear envelope has been reformed and the cell is currently undergoing cytokinesis to create two genetically identical daughter cells.

Answer 69

Firstly, 10 / 100 = 0.1, also known as 10% 10% are in metaphase in 15 hours 15 x 0.1 = 1.5 hours 1.5 x 60 = 90 minutes

Answer 70

The mitotic index is defined as the percentage of cells undergoing mitosis in a given population of cells.

Answer 71

To find the % of cells undergoing mitosis: 70 / 100 = 0.7 70%

Answer 72

A cancerous cell is a cell which divides uncontrollably, wherein they can form a tumor inside the organism.

Answer 73

A mutation in a gene that controls cell division may cause cells to grow out of control, causing cancerous cells which have uncontrollable cell division.

Answer 74

Cancer treatments that can't identify cancer cells among other cells mean that they will attack cells indiscriminately. This means that cancer treatments often aren't very efficient unless used in a large period of time, due to the fact that it can't target specifically what it's supposed to. As a result, cancer treatments are often needed in large doses to be effective, which can make the patient very ill from mass cell death.

Answer 75

It will kill itself (apoptosis), as it is unable to enter the Synthesis phase.

Answer 76

Just before and after the Synthesis phase If the cell is seen having dramatic damage to their DNA, the cell will kill itself by apoptosis.

Answer 77

The cells will kill themselves by apoptosis as a result of the drug due to the fact that there is a checkpoint just after and before the synthesis phase which checks for damaged DNA - severe damage will lead to apoptosis.

Answer 78

Firstly, grind up the cells you are going to be observing using a blender. This beaks up the plasma membrane and releases the organelles into the solution. The solution must be ice-cold, isotonic and buffered.

Answer 79

To reduce enzyme activity that break down organelles.

Answer 80

This is so the solution should have the same concentration as the cells to prevent lysis by osmosis

Answer 81

To maintain the pH to make sure cells don't get damaged or die if the pH level fluctuates and gets too high or low.

Answer 82

The homogenized cell solution should be filtered through a gauze to separate any large cell debris or tissue debris, like connective tissue, from the organelles. The organelles are much smaller than the debris, so they pass through the gauze.

Answer 83

After filtration, you're left with a solution containing a mixture of organelles. To separate a particular organelle from all the others, you must use them in a centrifuge. The cell fragments are poured into a tube which is put into a centrifuge and is spun at a low speed. The heaviest organelles, like nuclei, get flung to the bottom of the centrifuge. They form a thick sediment at the bottom known as the pellet. The rest of the organelles stay suspended in the fluid above the sediment, known as the supernatant. The supernatant is then drained off, poured into another tube and spun in the centrifuge at a higher speed. Again, the heaviest organelles, this time, the mitochondria, form a pellet at the bottom of the tube. The supernatant containing the rest of the organelles is drained off and spun in the centrifuge at an even higher speed. The process is repeated at higher and higher speeds, until all the organelles are separated out. Each time, the pellet at the bottom of the tube is made up of lighter and lighter organelles.

Answer 84

``` Nuclei Mitochondria Lysosomes Endoplasmic Reticulum Ribosomes ```

Answer 85

A supernatant is the liquid lying above a solid residue. This term is used in centrifugation in cell fractionation, wherein when the cell contents are initially spun in a tube, the nucleus (heaviest) lie at the bottom as a solid residue, and the rest lie above it as a liquid, known as the supernatant.

Answer 86

A solid residue, wherein cell fractionation is formed at the bottom of a centrifuge. For example, when initially having your cell contents spun in a centrifuge in cell fractionation, the nuclei (heaviest) sink to the bottom, becoming a solid residue. This is known as a pellet.

Answer 87

``` A = Plasma membrane B = Chloroplast C = Rough ER D = Plasmodesma E = Mitochondria F = Golgi Apparatus G = Vacuole H = Smooth ER I = Cytoplasm J = Nucleolus K = Nucleus L = Ribosome M = Cell Wall ``` Plant cell

Answer 88

https://media.discordapp.net/attachments/352951793187029005/838466235624062996/unknown.png - A sharp pencil must have been used when you made it - Label of the Nucleolus, Chromatin, Nuclear Pore, Nuclear Envelope is required, not the Nucleoplasm Label arrows must not overlap at all - Pens, including any colored pencil or pen, are not allowed.

Answer 89

https://media.discordapp.net/attachments/352951793187029005/838467494053675028/unknown.png - A sharp pencil must have been used when you made it - Label of the Matrix and Crista must be featured Label arrows must not overlap at all - Pens, including any colored pencil or pen, are not allowed. - A scale of x62,800 is required to be included on the image.

Answer 90

Cell wall - cell membrane is then under it in cells that do have a cell wall.

Answer 91

A tissue refers to a group of cells working together to form a particular function.

Answer 92

An organ refers to a group of tissues working together to form a particular function.

Answer 93

An organ system refers to a group of organs working together to form a particular function.

Answer 94

SEMs scan a beam of electrons across the specimen. This knocks off electrons from the specimen, which are gathered in a cathode ray tube to form an image.

Answer 95

TEMs use electromagnets to focus a beam of electrons, which is then transmitted through the specimen.

2A | Cell Structure and Division Flashcards

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