B1 - Cell structure and transport Flashcards
What organelles are found in a plant cell?
Ribosomes, Cell membrane, Cellulose cell wall, Mitochondria, Cytoplasm, Permanent vacuole, Chloroplasts, Nucleus
What organelles are found in an animal cell?
Cell membrane, Ribosomes, Mitochondria, Cytoplasm, Nucleus
What is a nucleus?
The nucleus controls all the activities of the cell and is surrounded by the nuclear membrane. It contains the genes on the chromosomes that carry the instructions for making the proteins needed to build new cells or organisms. The average diameter is around 10 micrometres (10 μm)
What is a cytoplasm?
The cytoplasm is a liquid gel in which the organelles are suspended and where most of the chemical reactions take place that are needed for life
What is a cell membrane?
The cell membrane controls the passage of substances such as glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.
What are mitochondria?
The mitochondria are structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell. They are very small:1-2 μm in length and only 0.2-0.7 μm in diameter
What are ribosomes?
Ribosomes is where protein synthesis takes place, making all the proteins needed in the cell
What are chloroplasts?
Chloroplasts are found in all the green parts of a plant. They are green because they contain the green substance chlorophyll. Chlorophyll absorbs light so the plant can make food by photosynthesis. Each chloroplast is around 3-5 μm long. Root hair cells do not have chloroplasts because they are underground and do not photosynthesise
What is a permanent vacuole?
The permanent vacuole is a space in the cytoplasm filled with cell sap. This is important for keeping the cells rigid to support the plant
What is a Cellulose cell wall?
A cellulose cell wall is a cell wall made of cellulose that strengthens the cell and gives is support
What are examples of eukaryotic cells?
Animal and plant cells
What are examples of prokaryotic cells?
bacteria
Are eukaryotic cells unicellular or multicellular?
unicellular or multicellular
Where is DNA stored in a eukaryotic cell?
In the nucleus
Do eukaryotic cells contain membrane bound organelles?
yes, they have membrane bound organelles
Are prokaryotic cells unicellular or multicellular?
unicellular
Where is DNA stored in a prokaryotic cell?
it is free floating
Do prokaryotic cells contain membrane bound organelles?
no, they do not have membrane bound organelles
Do eukaryotic cells have a nucleus?
yes
Do prokaryotic cells have a nucleus?
no
What is active transport?
the movement of substances from a dilute solution to a more concentrated solution against a concentrationgradient, requiring energy from respiration
What is algae?
simple aquatic organisms (protista) that make their own food by photosynthesis
What is an alveoli?
tiny air sacs in the lungs that increase the surface area for gaseous exchange
What is bacteria?
single-celled prokaryotic organisms
What is cellulose?
the complex carbohydrate that makes up plant and algal cell walls and gives them strength
What is diffusion?
the spreading out of the particles of any substance in a solution, or particles in a gas, resulting in a net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient
What are eukaryotic cells?
cells from eukaryotes that have a cell membrane, cytoplasm, and genetic material enclosed in a nucleus
What is hypertonic (osmosis)?
a solution that is more concentrated than the cell contents
What is hypotonic (osmosis)?
a solution that is less concentrated than the cell contents (more water outside cell)
What is isotonic (osmosis)?
a solution that is the same concentration as the cell contents
What is osmosis?
the diffusion of water through a partially permeable membrane from a dilute solution (which has a highconcentration of water) to a concentrated solution (with a low concentration of water|) down a concentration gradient
What is a partially permeable membrane?
a membrane that allows only certain substances to pass through
What is phloem?
the living transport tissue in plants that carries dissolved food (sugars) around the plant
What is plasmolysis?
the state of plant cells when so much water is lost from the cell by osmosis that the vacuole and cytoplasm shrink and the cell membrane pulls away from the cell wall
What are prokaryotic cells?
from prokaryotic organisms have a cytoplasm surrounded by a cell membrane, and a cell wall that does not contain cellulose. The genetic material is a DNA loop that is free in the cytoplasm and not enclosed by a nucleus. Sometimes there are one or more small rings of DNA called plasmids
What is resolving power?
a measure of the ability to distinguish between two separate points that are very close together
What is sperm?
the male sex cells or gametes that carry the genetic material from the male parent
What is stomata?
openings in the leaves of plants, particularly on the underside and opened and closed by guard cells, allowing gases to enter and leave the leaf
What is turgor?
the pressure inside a plant cell exerted by the cell contents pressing on the cell wall
What is ventilated?
movement of air or water into and out of the gas exchange organ, for example lungs or gills
What is xylem?
the non-living transport tissue in plants that transports water from the roots to the leaves and shoots
What type of cells contain plasmids?
Prokaryotic cells
What are plasmids?
plasmids are small rings of DNA that code for very specific features such as antibiotic resistance
What is a flagellum?
a long protein strand that lashes about to help bacteria move themselves around
What is a slime capsule?
A protective capsule that is around the outside of the cell wall on a bacteria cell
Describe the structure of a bacteria cell
Bacteria have cytoplasm and a cell membrane surrounded by a cell wall, but the cell wall does not contain cellulose like in plant cells.
Can bacteria colonies be seen with the naked eye?
yes
What does it mean if an object is 1 order of magnitude larger than another object?
it is 10x larger than the other object
Describe the method for looking at cells
1) Collect a sample of the cell you want to observe2) Remove the inner layer of onion skin using forceps3) Place the thin slice onto a clean glass slide. Use your forceps to keep the onion skin flat on the glass slide4) Using a pipette, add 1 or 2 drops of dilute iodine solution on the top of the onion skin5) Hold the coverslip by its side and lay one edge of the cover slip onto the microscope slide near the specimen6) Lower the cover slip slowly so that the liquid spreads out.7) Move the microscope stage to its lowest position8) Place a prepared slide on the centre of the stage and fix it in place using the clips.9) Select the objective lens with the lowest magnification10) Look through the eyepiece and turn the coarse focus adjustment until the cells on the slide come into view.11) Turn the fine focus adjustment to sharpen the focus so the cells can be clearly seen.12) If you wish to view the object at greater magnification to see more detail, repeat the above steps using a higher magnification lens.13) At a low magnification, place a transparent ruler across the microscope stage.14) Measure the width of the field of view using the ruler markings.15) Place the slide to be viewed into position. Increase the magnification until individual cells can be viewed16) Calculate the new width of the field of view at this magnification, using the formula: FoV = (original magnification / new magnification) x original FoV17) Count the number of cells visible across the field of view18) Calculate the length of a single cell using the following formula: Length of cell = FoV / No. Cells
What is magnification?
the number of times bigger something appears
What is resolution?
the ability to distinguish between 2 separate points
What is the maximum resolution of a light microscope?
200 nm