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