B1 (biology) Flashcards
What is an eukaryotic cell?
A cell that has its DNA contained in a nucleus
What is a prokaryotic cell?
A cell that has its DNA floaty freely in its cytoplasm
Give an example of eukaryotic cell
Animal and plant cells
Give an example of prokaryotic cell
Bacteria
What is the function of a nucleus ?
Contains the DNA and controls the activity of the cell
What is the function of mitochondria?
Where respiration takes place
What is the function of cytoplasm?
Where chemical reactions go in inside the cell (including anaerobic respiration)
(Supports internal cell structures)
What is the function of cell membrane?
Controls what enters and leave the cell
What is the function of the large vacuole?
Filled with cell sap,(a solution of sugars and salts dissolved in water) (acts like a water store in the cell)
(Also helps support the shape of the cell)
What is the function of the chloroplast?
contains chlorophll that Absorbs light for photosynthesis
What is the function of a cell wall?
Stops the cell from bursting and gives the organism a firm shape (strengths the cell)
(Made of cellulose) (a polymer of glucose)
What is the approximate size of a prokaryotic cell?
0.1-5.0 µm (micrometer)
What is the approximate size of an eukaryotic cell?
10-100 µm ( micrometer)
What is cell differentiation?
The process of cells becoming specialised to perform a particular function (this process is irreversible)
What is cell division?
The splitting of a cell into two genetically identical daughter cells
Name 3 specialised cells found in the animal and 3 in the plant
Animal : muscle cell, nerve cell , sperm cell
Plant : root hair cell, phloem , xylem
What is the function of a muscle cell?
Contract/relax the muscle for movement
State one adaptation of a muscle cell
Lots of mitochondria for releasing energy for contraction
What is the function of a sperm cell?
To swim/ find an egg cell and fertilise it
State three adaptation of a sperm cell
Flagellum (tail) to swim
Lots of mitochondria to release energy to move
Enzyme in its head (in the acrosome) to penetrate the egg (to break the egg’s cell membrane)
What is the function of a nerve cell?
Carry information as electrical impulses from one part of the body to another
State three adaptations of a nerve cell
Dendrites to connect to other neurones
Long axon to cover large distances
Myelin sheath to speed up impulses
What is the function of a root hair cell?
Absorb water and mineral ions from the soil
State two adaptations of a root hair cell
Large surface area (long extension) to icrease the rate of absroption
Lots of mitochondria to release energy for active transport of mineral ions
What is the function of a xylem cell?
Carry water and minerals from roots to leaves
State three adaptations of a xylem cell
Walls have lignin to give strength, stops it from bursting
No end walls (hollow tubes)
Made from thick dead tissues
State three adaptions of a phloem cell
Made from living tissue
End walls have sieve cells to help the glucose flow through and in the right directions
Lots of mitochondria for energy for active transport
What is the function of a phloem cell?
Transport glucose within a plant
What is used to stain plants to see them better under a microscope?
Iodine
What is used to stain animal cells to seem them better under a microscope?
Methylene
Define resolution
Resolution is the ability to distinguish two objects from each other.
Define magnification
Magnification is how many times bigger the image of a specimen observed in comparison to its actual (real-life) size. Magnification is the ability to make small objects seem larger, such as making a microscopic organism visible.
State the symbol equation for magnification
I=AM
State the word equation for magnification
Imagine size = actual size x magnification
Which microscope has the highest magnification?
Electron microscope
Which microscope has the lowest resolution (resolving power)?
Light microscope
What type of radiation is used for a light microscope?
Light
What type of radiation is used for an electron microscope?
Electron beam
What is the light microscope focussed by?
Glass lenses
What is the electron microscope focussed by
Electromagnets
What type of material can be viewed under the light microscope?
Any material live or dead
What type of material can be viewed under the electron microscope?
Specimin must be dead and dehydrated
What is the size like a for a light microscope?
Small and portable
What is the size like for an electron microscope?
Incredibly large, once it is installed it can not be transported
What preparation is needed to use a light microscope ?
No preparation
No need of specialist training
What is the preparation needed to use an electron microscope?
Special training needed to use it
What is the cost like for a light microscope?
Cheap
What is the cost for an electron microscope?
Expensive
Which microscope produces 3D images?
Scanning electron microscope
Define ‘cell’
The basic building blocks of all living organisms
Define tissue
A group of cells with a similar structure and function
Define organ
Aggregations of tissues performing specific functions
Define organ system
A group of different organs working together to fulfil a function
Define organism
Organ systems working together to form an organism
Put into order size (smallest to larges) : cell , organism , nucleus , tissue , organ system , organ
Nucleus
Cell
Tissues
Organ
Organ systems
Organism
What is the cell cycle called?
Mitosis
What is stage one called in mitosis?
Interphase
What happens in the interphase?
Cell grows
Chromosomes replicate
Organelles increase ( more mitochondria and ribosomes are made)
What is stage 2 called in the cell cycle?
Mitosis
What happens in stage 2 of the cell cycle?
Chromosomes line up in the centre of the cell
Chromosomes from each pair gets pulled to opposite ends
What is stage 3 called in the cell cycle?
Cytokinesis
What happens in cytokinesis?
Cytoplasm and cell membrane divides into 2 genetically identical daughter cells
What is meant by ‘centi’ ?
1/100th (1 hundredth of a meter)
What is meant by ‘mili’?
1/1000th (1 thousandth of a meter)
What is meant by ‘nano’?
1/1000000000th (1 billionth of a meter)
How do you convert from millimetre to nanometres?
X1000
What is the name of the cell that can differentiate into specialised cell?
Stem cell
State the importance of the cell cycle
More cells are made for growth and repair
Mitosis produces which type of cells?
Diploid cells
Define ‘stem cell’
An undifferentiated cell
define a bone marrow?
Found inside a bone that contains adult stem cells, that can only be turned into blood cells
Where in a plant can you find stem cells?
Meristem
What is a specialised cell? Give an example
A cell with a function e.g roothair cell
Name 3 places where stem cells can be found
Embryos , adult bone marrow , meristem
State 2 conditions that stem cells can be used to treat in humans
Paralysis
Type 1 diabetes
What is a clone?
A genetically identical organism which has been produced asexually
What does asexual mean?
Reproduction with one person
State 2 uses of stem cells in plants
Clone rare species
Produce disease resistant crops
Describe what is meant by ‘therapeutic cloning’
Using clones of a patient’s own stem cells to treat them
Which cells are required for therapeutic cloning?
Egg cell and a normal body cell from patient
State 2 objections to using stem cells in treatment
Potential transfer of viral infections
ethical / religious objections
What is the independent variable for the ‘potato osmosis practical’?
The concentration of the solution
What is the dependent variable for the ‘potato osmosis practical’?
The percentage change in mass
Name 5 control variables in the ‘potato osmosis practical’
Length of potato
Diameter of the potato
Volume of solution
Time potato is left in the solution for
Temperature of solution
Give 3 ways to make results accurate for the ‘potato osmosis practical’
Read the volume of the solution from the meniscus
Dab the potatoes dry before measuring the mass
Use a digital top pan balance
Name one risk and precaution of the ‘potato osmosis practical’
Risk=cutting yourself with the potato borer
Precaution= push the borer down towards the desk not upwards
What is the purpose of the distilled water in the ‘potato osmosis practical’?
To act as a control to compare your result to
How is the concentration inside the tissue estimated? For the ‘potato osmosis practical”
Plot a graph of concentration against % change in mass and find where the Line of best fit crosses 0%
How is the percentage change in mass calculated?
% change in mass = change in mass / initial mass
What is the percentage change calculated rather than just the change? For the ‘potato osmosis practical”
The potato may be slightly different sizes and shapes to begin with
Why does the tissue increase in mass for the ‘potato osmosis practical’?
Water has entered the tissue by osmosis in more dilute solutions
How can you tell if there has been an increase in mass?
The % change in mass is +ve
Why does the tissue decrease in mass?
Water gas left the tissue by osmosis in More concentrated solutions
How can you tell if there has been a decrease in mass?
The % change in mass -ve
What doe no change in mass mean?
The concentration of the solution is the same as the concentration inside the tissue
What are possible variations on this method? (Osmosis)
Using any other vegetable/ plants tissue
Using any other food substances
Using a salt solution
What is diffusion?
The overall movement of particles from a high concentration to a low concentration (down the concentration gradient)
(Passive process) requires no energy
What gets diffused out the bloodstream?
Carbon dioxide
Water
What gets diffused in the bloodstream?
Oxygen
Glucose
Two examples of diffusion in humans are:
CO2 + O2 in gas exchange , urea from cells to blood
What are the four factors that affects the Rate of diffusion?
Concentration gradient
Temperature
Surface area of the membrane
distance
What happens to the rate of diffusion as you increase the temperature?
Increases
What happens to the rate of diffusion as you increase the surface area?
Increases
What happens to the rate of diffusion as you increase concentration gradient?
Increases
What happened to the rate of diffusion as you increase the distance?
Decreases
How are single celled organisms adapted for diffusion?
Large surface area : volume ratio
How are the small intestine adapted for exchanging materials ?
Vili for large surface area
Vili are one cell thick (short distance)
Good blood supply (blood can flow so large concentration gradient)
How are lungs adapted for exchanging materials?
Alveoli large surface area: volume ratio
Surface is moist
Good blood supply
How are gills adapted for exchanging materials?
Large surface area
Moist
Good blood flow to maintain concentration gradient
Four ways to increase the rate of transport
Large surface area
Thin membrane
Efficient blood supply (in animals)
Well ventilated (in animals)
How are roots adapted for exchanging materials?
Large surface area to volume ratio
Lots of mitochondria for energy for active transport
What is the Equation for volume?
Height x width x dept
What is a solute?
Something that is dissolved into water
What is osmosis?
Water particles that move from a high water potential to a low water potential, through a partially permeable membrane
How do you calculate the % change?
Change in mass / start mass x 100
What is active transport?
Movement of particles from a low concentration to a high concentration
(It requires energy) (ATP)
(Against the concentration gradient)
Why will the pure water move into the potato?
The concentration of water is higher outside the potato
(RP) how can you tell the concentration of sugar in a piece of potato?
Place into different concentration of sugar solution
Plot graph
Find concentration where mass doesn’t change
When a substance moves against the concentration gradient , what is it called?
Active transport
What does active transport require?
It requires energy from respiration
What is the function of ribosomes?
The site of protein synthesis in the cell (the process of cells making protein) (found in the cytoplasm)
Where are the chloroplast found in a plant ?
Leaf
What are cell walls made from in a bacteria?
Peptidoglycan
What are the three types of muscle in an animal?
skeletal
smooth
cardiac (heart)
