Unit 1- cell biology Flashcards
Where is dna stored in bacteria cell
Plasmids
Magnification equation
Image size / real size
What is differentiation
When a cell becomes specialised for its job
Function of nerve cell
Carry electrical signals from one part of body to another
Function of muscle cell
To contract quickly
Function of root hair cell
Absorb water and minerals
Function of phloem and xylem
Transport substances such as food and water around plants
What is a stem cell
Undifferentiated cell
Where are adult stem cells found
Bone marrow
What may stem cells be able to do
Cure disease, replace faulty cells
Where are plant stem cells found
Meristem
What is mitosis
DNA is copied the cell then divides and produces two new daughter nuclei with exact same dna
What cells does mitosis take place
Eukaryotic cells
Why can embryonic stem cells treat more disorders that adult stem cells
Embryonic stem cells can develop into any stem cells although adult stem cells can only develop into particular ones
What is osmosis
Movement of water across partially permeable membrane from a dilute solution to a concentrated solution
What is diffusion
Spreading out of particles from high to low concentration
What is a partially permeable membrane
One with very small holes in it so only water can pass through
What is active transport
Substances (minerals )absorbed from a low to high concentration, needs energy from respiration to work
Where does active transport take place
Used in the gut and in root hair cells
How are exchange surfaces adapted to maximise effectiveness
Thin walls
Large surface area
Good blood supply
Where does plant diffusion take place
Stomata
What is the cell cycle
Makes cells for growth development and repair
Centimetres to micrometers
x 10,000
Similarities with eukaryotic and prokaryotic
Both contain chloroplasts
Both contain genetic material
Differences between prokaryotic and eukaryotic
Prokaryotic have no nucleus
Prokaryotic have plasmids
Prokaryotic are smaller
One type of cell in a potato that does not contain chloroplasts
Root hair cell
Why did the potato piece salt solution decreased in mass
Water moved out of cell by osmosis
Because solution in potato is less concentrated than outside
Why is the cover slip at an angle for microscope RPA
To prevent air bubbles
How does mitosis form 2 genetically identical cells
Chromosomes pulled apart
DNA is copied
Two new nuclei form
Set of chromosomes are identical to one another
Cell that doesn’t contain nucleus
Bacteria, prokaryote , xylem
Reason for reduced number of deaths of malaria this year
Improved health care
Describe the transport of water through a plant from the roots to atmosphere
-water is transported in xylem
-water evaporates from leaves
-through stomata
Two reasons why water loss increased
It was warmer
It was windier
Evaluate use of mechanical and biological heart replacements
Mechanical:
-last longer
-bloods clots more likely
-have to take anti clotting medication
-medication can lead to excessive bleeding
-low percentage of deaths due to heart related problems
Biological :
-no medication required
-ethical issues
-valve may harden
-more likely to be rejected
- likely to need further operation
Explain how diabetes can cause the body to lose more water
Blood is more concentrated
So water moves out of cell by osmosis
Water moves across partially permeable membrane
How is small intestine adapted for absorption
-Villi provide large surface area to volume ratio
-capillaries are thin for short absorption distance
-small intestine is very long
-good blood supply to maintain concentration gradient
-cells have many mitochondria for aerobic respiration for active transport
Define double circulatory system
-Blood is pumped to the lungs by right side of the heart
And
-blood is pumped to the body by left side of heart
Why does only having on ventricle make circulatory less efficient than having two ventricles
Oxygenated and deoxygenated blood mix
So less oxygen reaches body
One condition that could be treated by regenerated human tissue
Paralysis
Which part of microscope is used to change magnification
The objective lense
Function of cell membrane
Determine what goes in and our of cell
Function of cell wall
Important for structure
Function of cytoplasm
Where most chemical reactions take place in the cell
Function of nucleus
Where dna is stored
Differences between plant cell and animal cell
Plant cell contains cell wall, vacuole and chloroplasts and animal cell doesn’t
Main different characteristics of a bacterial cell
Contains a flagellum which helps assist the cell in movement
Name the blood vessel that carries blood towards heart
Vein
What is a eukaryotic cell
Contain their genetic material enclosed in a cell examples include animal and plant cells
What is a prokaryotic cell
The genetic material is not enclosed in a nucleus (examples include bacterial cell)
What is the size of a typical human cell
10-20 micrometers
Centimetres to nanometers
x10,000,000
Function of mitochondria
Where aerobic respiration occurs
Function of sperm cell
Join with an egg cell (fertilisation)
How are sperm cells adapted
Long tail which allows them to swim to the ovum
They are also streamlined to make this easier
Lots of mitochondria to produce lots of energy needed to swim
Contain enzymes which allow them to digest their way through the outer layer of the ovum
Adaptations of a nerve cell
Axon carries the electrical pulses from one part of the body to another
End of action synopses which allows impulses to jump from one nerve cell to another
Dendrites which increase the surface area so that other nerve cells can connect easier
Adaptations of a muscle cell
-contain protein fibres which can change their length
-packed with mitochondria to provide energy for muscle contraction
-work together to form muscle tissue
Function of a vacuole
Filled with cell sap to help keep the cell turgid
Adaptation of a root hair cell
Hairs help increase the surface area so can absorb water and minerals more effectively
Do not contain chloroplasts
Why cant a root hair cell photosynthesise
Don’t contain chloroplasts because they are underground so sunlight doesn’t reach them
Where are xylem cells found in the plant
In the plant stem
Adaptations of a xylem cell
Thick walls containing lignin which provides the plant support
Made of dead cells
No nucleus, cytoplasm, vacuole or chloroplasts
Hollow
Adaptations of a phloem cell
No nucleus and limited cytoplasm
Cell walls between he cells break down to form special sieve plates, these allow water carrying dissolved food to move freely up and down tubes to where it is needed
Have pores in the end of walls, so dissolved sugars contents can move from cell to cell
Made of living cells
What is binary fission
One bacterial cell splits into two bacterial cell
Bacteria can carry out binary fission once every 20 minutes as long as there is enough nutrients and the temp is suitable
How to calculate number of bacteria produced during binary fission
Number of bacteria = 2 to the power of the number of rounds of division
Functions of mitosis
- Essential for growth and development of multicellular organisms (plants and animals)
- Mitosis takes place when an organism repairs itself (when a broken bone heals)
Name of a cell that has not differentiated
Early embryonic cell
Bits of equipment used to prepare cell for magnification
A slide, dye
Features of a red blood cell
Has no nucleus
No cell wall
Biconcave
Contains haemoglobin
no chloroplasts
No vacuole
Contains cytoplasm, cell membrane
What is human body temperature
37 degrees
How to calculate total magnification
Magnification of eye piece x magnification of objective lens
How to create magnification scale
Place clear ruler over stage
Measure diameter of field of view
Show this on our drawing using a scale bar
How do you avoid contamination when making agar plate
- Sterilise all pétri dishes
- Pass incubating loop through Bunsen Burner
- Attach lid using adhesive tape to stop microorganisms from entering
What do you call the region where bacteria has not grown
Zone of inhibition
What are bacteria transferred using in the bacteria RPA
Inoculating loop
What temperature should we incubate bacteria in school and why not at 37 like in labs
25 degrees as this reduces chance that harmful bacteria will grow, 37 degrees is human body temperature so it will grow best then
How to work out zone of inhibition
Pi x R squared
Why is distilled water used not tap water in osmosis RPA
Distilled water no other substances as they could affect the rate of osmosis
What is a cork borer used for in osmosis RPA
To make all the cylinders the same diameter
Grams to milligrams
X1000
Advantages of sexual reproduction
-Produces variation in the offspring
-The species can adapt to new environments due to variation, which gives them a survival advantage
-A disease is less likely to affect all the individuals in a population
What is asexual reproduction
Only one parent is needed in asexual reproduction
There is no fusion of gametes so genetic material does not mix
What is sexual reproduction
Two parents are needed in sexual reproduction
During this process the nuclei of the male and female gametes are fused in order to create a zygote. This process is known as fertilisation
Advantages of asexual reproduction
-the population can increase rapidly when the conditions are favourable
-only one parent is needed
-it is more time and energy efficient as you don’t need a mate
-it is faster than sexual reproduction
Disadvantages of sexual reproduction
-time and energy are needed to find a mate
-it is not possible for an isolated individual
Disadvantages of asexual reproduction
-it does not lead to variation in a population
-the species may only be suited to one habitat
-disease may affect all the individuals in a population
Differences between asexual and sexual
Sexual involves fertilisation, asexual does not
Sexual requires more energy, asexual does not
Sexual is slower, asexual is faster
Why does red blood cell burst but plant cell does not
Water has entered cell by osmosis however plants cell has cell wall which prevents it from bursting
Differences between process of mitosis and meiosis
Mitosis produces 2 daughter cells but meiosis produces 4 daughter cells
One cell division in mitosis but 2 in meiosis
Meiosis produces haploid cells mitosis forms diploid cells
Similarly between meiosis and mitosis
Both copy DNA
What is therapeutic cloning
-an embryo is produced with the same genes as the patient
-stem cells from the embryo are not rejected by the patients body so they may be used for medical treatment
-risks such as transfer of viral infection and some ethical or religious objections
What can plant stem cells do
-can be cloned quickly and economically so :
-rare species can be cloned to protect from extinction
-crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers
Factors which affect the rate of diffusion
-the difference in concentrations
-the temperature
-the surface area of the membrane
What happens if solution outside cell becomes more dilute (higher water concentration and lower concentration of sugar)
Water will move out by osmosis
The cell will swell and may burst
What happens if solution outside celle become more concentrated (low concentration of water high concentration of sugar)
Water will move out of the cell by osmosis
Cytoplasm will become too concentrated and cell will shrivel and can no longer survive
