Exam Q - Cells
Describe the functions of glycoproteins in the cell surface membrane
Glycoproteins act as antigens, in that they are used for the recognition of cells as being self/non self, they are used for cell signalling, they have receptors for hormones, and the receptors can be triggered on a transport protein. They act as an adhesive to help bind cells, and they attach to water molecules to stabilize the membrane
What name is given to proteins with sugars attached
Glycoprotien
Explain the meaning of the term tissue
Group of cells of one or more types with intracellular material specialized to perform a particular function
What process occurs during the stages G1 and G2
Growth of the cell organelles, increase in number of organelles and the synthesis of proteins
Haploid
Individual chromosomes
Describe the behavior of chromosomes in metaphase
Individual chromosomes align at center of the cell and they then join to the spindle by their centromeres
What stage of mitosis does the DNA replicate
Interphase
How can a glycoprotein act as a receptor
It has a specific shape, which is complementary to the shape of he trigger molecule, the trigger binds with the receptor
Why is it important red blood cells are stored in a solution with a suitable water potential
It prevents osmosis, as there is no net movement of water, and it prevents bursting/lysis/crenation of the cell
What functions of mitosis are there
Produces genetically identical cells, for asexual reproduction, it maintains the chromosome number, it helps in the growth of organisms, and for the replacement of cells
What are the differences between prokaryotic and eukaryotic cells
Prokaryotic cells have no true nucleus, have circular DNA, their genetic material consists of 'naked' DNA, their average diameter is 0.5-5um, their ribosomes are 18nm, 70s, and they always have a murein cell wall present, have no histones, has membrane organelles, has plasmids, doesn't have a cytoskeleton whereas Eukaryotic cells have their genetic material held in a nucleus, have linear DNA, their genetic material is in the forms of chromosomes and is associated with proteins, the diameter of the cell is 20-40um, their ribosomes are about 22nm, 80s, in diameter, and a cellulose cell wall is sometimes present, have histones, has membrane organelles, doesn't have plasmids, has a cytoskeleton
What is the stage of mitosis where the chromosomes become visible
Prophase
What stage of mitosis do chromosomes become visible as two chromatids
Prophase
What type of epithelial tissue is found in the lungs
Squamous, Cilliated, (endothelium)
Outline the roles of glycoproteins in membranes
Stabilize membrane structure by forming hydrogen bonds with water molecules, antigens for cell recognition, binding sites for antibodies, receptors for cell signaling
What is the stage of mitosis where the nuclear envelope re forms
Telephase
What stage of mitosis does the nuclear envelope reform
Telophase
Why can lungs be considered organs
The lung is an organ as it is a collection of tissues working together to enable gas exchange
Describe the process of endocytosis
The membrane folds in and engulfs the substance, it then fuses with itself pinches of and forms a vesicle, the vesicle then moves through the cytoplasm, can be triggered by the binding of the molecule to the receptor site
Name a structure associated with the cytoskeleton which can bring about cell movement
Cilia, Flagella, microtubles, microfilamanets, undulipodium
What is meant by the term cell signalling
Communication between cells, for cell recognition/identification, so cells can work together and coordinate different actions, and to trigger a response inside the cell
How is the structure of a sperm cell specialized for its function
Flagellum for movement, chromosomes in haploid nucleus for fertilizing egg, head shaped for penetrating the egg cell, has many mitochondria for energy
What is the name given the the model of a membrane structure
Fluid mosaic model
How can small non polar substances enter a cell through the plasma membrane
They can diffuse through the phospholipid bi layer
How are red blood cells adapted to their function
They contain Hemoglobin which carries oxygen, it can carry 4 oxygen molecules at once, it has a small size and a large SA:V, this means that the haemoglobin is never far from the call surface, it is flexible,and small in size which allows it to squeeze into capillaries, it has a biconcave shape, which increases the surface area relative to the volume, it has no nucleus to maximize space for the haemoglobin, and it contains carbonic anhydrase, which catalyses reactions to maintain the diffusion gradient, carbaminohaemoglobin transports the CO2, providing a buffering effect
How can polar substances enter a cell through the plasma membrane
They enter the cell through channel proteins using transport proteins, they can do this through facilitated diffusion passively, or by active transport with the use of ATP
How can large substances enter a cell through the plasma membrane
They use transport/carrier proteins and use endocytosis/phagocytosis
Why is the vacuole in a plasmolysed cell small
Water leaves the vacuole as it has a higher water potential, therefore the vacuole has lost more water so has shrunk
What happens to a cell if it is placed into a strong sugar solution
Water moves out of the cell by osmosis, as the cell has a higher water potential than the surrounding solution, the water moves down the water potential gradient from high to low water potential
Name an example of a plant tissue
Xylem, Phloem, epidermis, mesophyll, palisade, meristem, cambium...
What functions of glycoproteins are there in plasma membranes
Cell recognition, as receptors, and for holding enzymes
What is the maximum resolution achieved by a light microscope
1,500x
Circulation
10, 11, 12, 24, 25, 30, 31, 40, 41, 47, 49, 50, 51, 60, 61, 62, 63, 66, 71, 72, 73, 75, 76, 77, 85, 88, 89, 90, 94, 96, 97, 98, 106, 107, 108, 109, 119, 120, 121, 122, 130, 131, 132, 135, 136, 143, 146, 147, 153, 154, 161
Questions for module 2
3, 9, 11, 12, 13, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 40, 41, 46, 47 48, 49, 50, 51, 52, 53, 54, 59, 60, 61, 64, 65, 67, 70, 71, 72, 73, 74, 75, 76, 77, 78, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 96, 97, 98, 101, 102, 103, 104, 105, 106, 107, 108, 109, 111, 113, 114, 115, 115, 117, 118, 119, 120, 121, 122, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 140, 142, 145, 145, 146, 147, 151, 153, 154, 155, 156, 157, 158, 159, 163
Plants
3, 9, 18, 26, 27, 28, 29, 33, 34, 52, 53, 54, 64, 65, 67, 74, 78, 91, 92, 93, 101, 102, 103, 105, 111, 115, 116, 117, 118, 128, 129, 133, 134, 137, 140, 144, 145, 155, 158, 159, 160
State the number of chromosomes present in the nucleus of a liver cell
46
What is the maximum resolution achieved by a transmission electron microscope
500,000x
What is meant by the term tissue
A collection/group of cells of one or more type working together towards the same function, they are specialized cells
What is meant by the term resolution
Ability to see two objects that are close together as separate objects, so you can see *detail* in a picture
What is the stage of mitosis where the chromatids move towards the poles
Anaphase
What is the stage of mitosis where the spindle micro tubules shorten
Anaphase
How is the wall of an artery different from the wall of a vein
Arteries have no valves, their endothelium is folded, they have more muscle and elastic tissue, and have more thicker collagen
Outline the roles of membranes at the surface of cells and within cells
At surface: The membrane separates the cell from the enviroment, it controls entry/exit of molecules ions and substances, the phopholipid bi layer allows or prevents passage of substances, it allows for facilitated diffusion, for active uptake, for exocytosis and endocytosis, for cell recognition/and cell surface antigens, for cell to cell attachment, as a receptor. Within: membranes help compartmentalize organelles, prevents disruptions of reactions, it allows for reactions to take place on the membrane and for enzymes to attach them selves to the membranes, they can isolate the DNA in the form of the nucleus, nuclear pores allow RNA to leave nucleus, it helps form the Golgi/ER and forms vesicles, it allows for the attachment of ribosomes, and for intracellular transport, they can protect the cells from the contents of a lysosome,
Why would an image drawn to the same magnification as an electron microscope from a light microscope be of little use when studying cells
Light microscopes have a low resolution, so close points aren't easily distinguishable, this is because the wavelength of light is too long, because of this the max resolution is 200nm which means that anything close together wont be visible
How mights cells produced by mitosis differ than those produced by meiosis
Meiosis produces haploid cells (half the genetic information/chromosomes) the genetic information isnt identical and 4 cells are produced
Membranes
Membranes have a variety of functions in cells. All membranes are partially permeable. This means that they allow the passage of certain substances by processes such as active transport or facilitated diffusion through the membrane. The cell surface membrane, also known as the plasma membrane, surrounds the cytoplasm. The cell surface membrane consists of a bi layer of phospholipids. To stabilize the structure of the membrane and keep it fluid, molecules of cholesterol are also found in this bi layer.
What is the stage of mitosis where the chromosomes align at the equator
Metaphase
Mitosis
Mitosis is a type of nuclear division and can be observed using a light microscope. In the first stage, known as prophase, the chromosomes become visible. Each chromosome is seen as two chromatids joined at the centromere. The nuclear envelope breaks down, a spindle is formed and the chromosomes line up at the equator. During the stage known as anaphase the chromatids separate, one of each pair moving to opposite ends of the spindle. Separate nuclei are formed. The cytoplasm is then shared between the daughter cells in a process known as cytokinesis. These two cells are genetically identical
why is mitosis important to organisms
Mitosis is important for the growth of tissues and organs, for the replacement of cells and to repair tissue, it is used in asexual reproduction producing genetically identical cells, and it maintains the chromosome number in all cells
Which processes inside cells rely on the cytoskeleton for movement
Movement inside cells of chromosomes in cell division, of the cytoplasm in cytokinesis, organelles, RNA, and proteins
What might happen if the genetic material isnt checked
Mutation/faulty DNA produced as there's an error in copying, daughter cells will not receive identical genetic information, proteins made by the daughter cells aren't able to do their functions
Outline the functions of each part of a plant cell
Nucleus - controls activities of the cell, and contains the genetic information that can be transmitted to the next generation nucleolus - produces ribosomes Smooth ER - makes/transports lipids and hormones Rough ER - protein synthesis and transport of proteins Golgi - processes molecules/proteins, use in secretion, and for lysosome formation Lysosome - contains digestive enzymes, and is used for the breakdown of organelles Mitochondria - formation of ATP, and aerobic respiration Plasma membrane - controls exchange between cell and enviroment, receptors for cell recognition, fluid to allow endocytosis and exocytosis Cell wall - gives cell strength, prevents bursting, fully permeable Chloroplasts - used for photosynthesis, contains chlorophyll to absorb light Vacuole - reservoir of salts/sugars/ and other substances, used for controlling water potential Starch - Used for storage Cytoplasm - the site of chemical reactions
Diploid
Pairs of chromosomes
What happens to chromosomes during the mitotic cell cycle
Prophase - the chromosomes condense, and become visible as they are now shorter and thicker, they consist of two chromatids joined by a centromere Metaphase -The chromosomes align at the equator and are attached to the spindles by their centromeres Anaphase - The centromere splits, the chromatids separate and move to opposite sides of the cell by shortening of the spindle Telophase - The chromosomes uncoil Interphase - DNA replicates, and mRNA forms, it is early prophase
Outline the sequence of events following the production of extracellular proteins that leads to their release from the cell
Proteins are made in the RER, they are then moved to Golgi apparatus where they are processed/modified into vesicles, the vesicles are moved to the plasma membrane where they fuse with the membrane to be released from the cell by exocytosis
Ovary cells contain large amounts of ER, what is the importance of this in using the cells for the production of factor VIII
RER has ribosomes for protein synthesis, ER transports protein through the cell, it forms vesicles for transport to the Golgi which modifies the proteins
Outline the roles of the Golgi apparatus
Repackage/transport proteins, add carbohydrate group to proteins
What process must occur in a cell during inter-phase before mitosis can take place
Replication of DNA, centrioles replicate, production of organelles, protein synthesis, RNA synthesis, reparations, and active transport
plasmolysed
cytoplasm shrinks and membrane pulls away from cell wall when water leaves the cell.
Outline the roles of ribosomes
it is the site of protein synthesis
name the type of nuclear division that produces a liver cell
mitosis
