B1 Cells And Transport Flashcards
Electrons microscope magnification
1,000,000x
250x resolving of a light microscope
Why microscopes are useful in the study of cell biology
Scientists use microscopes to provide higher magnification, higher resoltion and more detail than light microscope
Most cells cannot be viewed by the naked eye
Advantages of using a light microscope
Simple to use
Doesn’t require the use of high voltage power
Disadvantages of using a light microscope
Low resolving power
Poor surface view
Resolving power
The ability to see two points as two points, rather than merged into one
Advantages of using electron microscope
High resolution
High magnification
Disadvantages of using electron microscope
Inability to analyze live specimens
Only black and white images can be viewed with electron microscope
Use of electron microscope
Used to study detailed structure of tissues, cells, organelles
Total magnification
Objective lens x ocular lens
How to calculate magnification
Size of image/size of real object
Parts of animal cell
Cell membrane
Nucleus
Cytoplasm
Mitochondria
Ribosomes
Parts of plant cell
Chloroplast
Cell wall
Cell membrane
Nucleus
Vacuole
Ribosomes
Mitochondria
Cytoplasm
Compare plant cell and animal cell
Plant cells have a cell wall in addition to a cell membrane, whereas animal cells have only a cell membrane
Why some cells do not contain all cell structures
The cells is created with the approximate structure to fit the environment
How to prepare a microscope slide
Peel a thin transparent layer of a cell from the inside of an onion
Place cells on microscopic slide
Add a drop of water or iodine
Lower a coverslip onto the onion cells
How do you use a microscope to see a plant cell
Prepare a thin plant tissue section
Apply a stain for visibility
Place section on a slide with water
Add coverslip to hold the section
Set microscope to low magnification
Increase magnification gradually
Prokaryotic cell
Simple cells that lack a nucleus and other membrane-bound organelles
Eukaryotic cell
Complex cells that contain a nucleus and other membrane-bound organelles
Structures in prokaryotic cells
Plasma membrane
Cell wall
A capsule
Structures in eukaryotic cells
Mitochondria
Chloroplast
Lysomes
How the main structures of prokaryotic cells are related to their functions
Flagella and some pili used for locomotion
How the main structures of eukaryotic cells are related to their functions
Plasma membrane separates internal contents of cell from its surrounding environment
Calculations to work out orders of magnitude
If increase a number by 1 order of magnitude you are multiplying the number by 10
If decrease a number by 1 order of magnitude divide the number by 10
Specialised cells examples
Red blood cells
Sperm cells
Egg cells
Nerve cells
Muscle cells
Villi
Why animals have specialised cells
To carry out a particular role in the body
How the structure of specialised animal cells are related to their function within the organ and whole organism
Their structure is adapted to their function
Compare the structure of a specialised and generalised animal cell
Generalised cells have a simple structure and can perform basic functions
Specialised cells have a more complex structure adapted to perform a specific function in the body
How animal cells are adapted
Disc-shaped to absorb oxygen more quickly and rounded to flow easily through tiny capillaries
Specialised plant cells examples
Guard cell
Xylem cell
Phloem cell
Root hair cell
How to predict which way substances will
move across a cell membrane
Any substance that can move down its concentration gradient across the membrane
How temperature affects rate of diffusion
Higher temperatures increase the energy and therefore the movement of the molecules, increasing the rate of diffusion
How concentration gradient affects rate of diffusion
The bigger the difference
the steeper the concentration gradient
the faster the molecules of a substance will diffuse
Why surface area affects the rate of diffusion
Aa surface area increases rate of diffusion increases
More space for molecules to diffuse across the membrane
What happens if anima cell lose or gain too much water
They stop working properly
Use ideas about osmosis to explain
why maintaining constant internal
conditions in living organisms is important
It stabilizes the internal environment of a living organism by maintaining the balance between water and intercellular fluid levels
Isotonic
Any external solution that has the same solute concentration and water concentration compared to body fluids
Hypotonic
Any external solution that has a low solute concentration and high water concentration compared to body fluids
Hypertonic
Any external solution that has a high solute concentration and high water concentration compared to body fluids
What happens if a plant loses too much water from its cells
They become soft
Active transport
Particles can move up the concentration
gradient if energy is used
Why active transport is important for living organisms
It is crucial for cell survival and rapid nutrient absorption by the cells
How active transport takes place
When molecules move from an area of high concentration to an area of low concentration
Where active transport takes place
Across the root so the plant takes in the ions from the soil around it
Does diffusion need to go through a partially permeable membrane
Does not need a partially permeable membrane
Does osmosis need to go through a partially permeable membrane
Yes
Does active transport need to go through a partially permeable membrane
Yes
It requires a partially permeable membrane
The function of exchange surfaces in plants and animals
The place substances are moved across membranes in an organism
How the effectiveness of exchange surfaces is increased
Large surface area
Ratio of single-celled organism
Large surface area to volume ratio
Ideas about surface area to volume ratio to describe why multicellular organisms need exchange surfaces
Cells too deep within their body so their body surfaces alone are not sufficient for the exchange of substances with their environment
How to calculate the surface area to volume ratio of a cube
Surface area
______________
Volume
Calculate the surface area to volume ratio of a cylinder
Surface area = x^2
Volume = x^3
Volume ratio = surface area ➗ volume
How to calculate surface area to volume ratio of a sphere
The ratio of surface to volume is 3/r
