Cell Biology Flashcards
What are animal and plant cells?
Eukaryotic cells
What’s the purpose of a cell membrane?
It is a protective barr around the outside of the cell. It controls which substances can pass in and out of the cell.
What is the purpose of the nucleus
It contains genetic material/DNA of the cell, and so controls what the cell does
What is the purpose of the cytoplasm
Its a gel like substance containing nutrients and salts where the chemical reactions take place
What’s the job of the mitochondria
They carry out aerobic respiration. It provides cells with the energy they need to function to use in chemical reactions (they break down sugars (eg. Glucose)
What do ribosomes do?
It’s where protein is made
What are bacteria cells
Prokaryotic cells “unicellular = 1 cell” (much smaller in comparison to plant and animal cells)
What is the use of a circular strand of DNA/nucleoid/circular chromosome?
it’s contains the genes they need to survive and reproduce. (The genetic material is not enclosed in a nucleus)
The use of plasmids?
They carry extra genes like antibiotic resistance (not needed on a daily basis but may come in handy)
What is flagella?
It helps propel the bacteria (allows the bacteria to move)
What is the cell wall made out of and what does it do?
The cell wall is made out of cellulose. It makes it stronger and allows it to maintain the shape of the cell.
What do plant and algal cells have in common? What does it help with?
They both have a cell wall made of cellulose which strengthens the cell
How does a chloroplast function?
It’s an organelle that contains the green pigment (chlorophyll) and it contains the enzymes needed for photosynthesis. It absorbs light energy for photosynthesis
What is the purpose of the permanent vacuole?
It’s filled with a solution of salt, sugar and organic acids (cell sap). The permanent vacuole helps keep the cell strong and gives it shape (supports the cell membrane - the thin skin around the cell) it also controls what passes in and out of the cell.
What is a cell?
A cell is the smallest unit of life that can live on it own. Cells make up all living organisms and their tissues.
What is enclosed within the nucleus for eukaryotic cells?
Cell membrane
Cytoplasm
Genetic material
what is the formula for magnification?
Magnification = image size/real size
real size = image size/magnification
image size = magnification x real size
What does the nucleus of a cell contain?
It contains chromosomes made of DNA molecules.
What do each chromosome carry
Each chromosome carries a large number of genes (Different genes control different characteristics. Eg. hair, eyes)
How do cells divide
They divide in a series of stages called the cell cycle.
What are chromosomes normally found in
In the body cells the chromosomes are normally found in pairs
Describe the stages of the cell cycle including mitosis
The genetic material is doubled and then divided into two identical cells before a cell can divide it needs to go and increase the number of sub-cellular structures such as ribosomes and mitochondria the DNA replicates to form two copies of each chromosome.
In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides.
Lastly the cytoplasm and the sun membrane divides to form two identical cells.
Why is cell division by mitosis important
Cell division by mitosis is important in the growth and development of multicellular organisms
How many chromosomes does a human cell have
23 pairs of chromosomes
Why do multicellular organisms use mitosis
To grow or replace cells that have been damaged
What’s the importance of cell differentiation
It allows the cell to specialize and perform specific functions in the organism
What type of specialization can animals cells carry out to function?
Sperm cells
nerve cells
muscle cells
What type of specialization can plant cells carry out to function?
Root hair cells
Xylem
Phloem
As an organism develops what happens to the Cell
The cell differentiate to form different types of cells
Most types of animal cells differentiate at an…
early stage
Many types of plant cells retain the ability to…
Differentiate throughout life
Stem cells are called?
Undifferentiated cells of an organism (not specialized)
why are electron microscopes at an advantage?
Electron microscopes have a much greater magnification and resolution then light microscopes.
How can having a higher magnification and resolution power benefit when studying cells?
It can be used to study cells in much finer detail and it allows biologists to see and understand many subcellular structures.
Explain how microscope techniques have developed over the time?
Improvements in lens manufacture help to solve problems like color and image resolution
Mature animals cell division is mainly restricted to what?
Repair and replacement
For cells to differentiate what do they need to become
They require different subcellular structures to enable to carry out a certain function (They become specialized cells)
What is the job of a sperm cell
Is to join with the ovum (egg cell) (Fertilization) 
What happens to the ovum and the sperm cell during fertilization
There Genetic information is combined
What’s the purpose of enzymes in a sperm cell
Allows them to digest their way through the outer layer of the ovum 
What’s the purpose of a nerve cell
Body sends electric impulses around the Body
What’s the purpose of an axon in the nerve cell
It carries the electric impulses from one part of the body to another
What are the axons covered in? do what do they help with?
Myelin. It helps speed up the transmission of the nerve impulse
What are synapses for the nerve cell
The end of the axon has synapse. synapse allow the impulses to pass from one nerve cell to another
What do dendrites do for the nerve cell
They increase the surface area so that other nerve cells can connect more easily
What do muscle cells contain
They contain protein fibers which can change the length
What do muscle cells form when they work together
Muscle tissue
Why does the surface area of roots hair cells increase
So it can absorb the water and dissolved minerals more effectively
Where is Xylem found?
In the plant stem. They form long tubes
What does xylem carry out
These tubes carry out water and dissolved minerals from the roots to the leafs 
Xylem cells have very thick walls containing what
Lignin (It provides support to the plant)
What do phloem cubes and sieve plates carry out
Both dissolved sugars up and down the Plant
What is the equation for the number of bacteria
2 ^n
N=Number of rounds of division

How does bacteria reproduce
By binary fission
Mitosis happens during…
Asexual reproduction
What is a stem cell?
A stem cell is an undifferentiated cells which can give rise to more cells of the same type of differentiate to form other types of cells
Where can you find stem cells in the adult
The stem cells in bone marrow differentiate to form cells found in our blood (eg. platelets, red blood cells and white blood cells)
What do roots and buds contain
Meristem tissue 
What can meristem tissues differentiate into
Is stem cells can differentiate Into any type of plant tissue at any point in the life of the plant
Stem cells from human embryos can be…
Cloned and made to differentiate into most different types of human cells
Treatment of stem cells may be able to help conditions(Therapeutic cloning). what type of conditions?
Diabetes and paralysis 
Describe the bone marrow transplant
Leukemia is a cancer of the bone marrow
The patient’s existing bone marrow is destroyed using radiation
The patient receives a transplant of the bone marrow from a donor.
The stem cells in the bone marrow divides and forms new bone marrow .
They also differentiate and form new blood cells.
What are the problems of bone marrow transplant
The donor has to be compatible with the patient otherwise the white blood cells produced by the donating bone marrow could attack the patient’s body
There’s a risk that viruses can be passed form the donor to the patient

What are enzymes
Enzymes are protein molecules
Describe therapeutic cloning
In therapeutic cloning an embryo is produced with the same genes as the patient
Stem cells from the embryo can be transplanted into the patient without being rejected by the patient’s immune system
Once inside the patient the stem cells then differentiate to replace cells which have stopped working correctly
What are some of the problems with therapeutic cloning
Some people have ethnical or religious objections to this procedure
Stem cells form … in plants
Meristems
Meristems can be used to produce … of plants quickly and economically
Clones
Rare species can be cloned to be protect from …
Extinction
What are crop plants with special features be used for?
Disease resistance. They can also be cloned to produce large numbers of identical plants for farmers.
Define diffusion
Diffusion is the spreading out of particles resulting in a net movement from a area of higher concentration to a lower area of concentration
Why are cells surrounded by a high concentration of oxygen
Oxygen is transported in the bloodstream of the lungs
Why is oxygen used in diffusion
To generate energy in respiration and this produces the waste gas carbon dioxide
Urea is a waste product produced where
Inside cells
How does urea diffuse
It diffuses out of the cell into the blood plasma and is excreted by the kidneys
What is the name of concentration in Diffusion
Concentration gradient (The greater the concentration gradient the faster diffusion takes place)
If the temperature is high in diffusion what does that mean
The higher the temperature the greater the rate of diffusion. This is because the particles have more kinetic energy and are moving faster.
How does a larger surface area help diffusion
The larger the surface area of the cell membrane the greater the rate of diffusion.
How do substances move in and out of the cells across the cell membrane
Via diffusion
What substances are transported in and out of the cell by diffusion
Oxygen and carbon dioxide in gas exchange.
Urea from the cells as a waste product.
A single-celled organism such as amoeba can rely on…
Diffusion to transport molecules in and out of the cell
Define osmosis
Osmosis is the movement of water molecules across a partially permeable membrane from a dilute solution to a concentrated solution
Define active transport
Active transport is the movement of substances against the concentration gradient. This process requires energy from respiration. Active transport is the movement of substances from a dilute solution to a concentrated solution.
The cytoplasm has a relatively concentrated solution this means that
It contains a low concentration of water but a high concentration of sugar 
If an animal cell was inserted into water what could happen
The water moving work on the cell to expand or even burst
If we place an animal cell into a very concentrated solution what will happen
The water will move out of the cell by osmosis and the cell will shrink
If you place a plant cell in a diluted solution (osmosis) what will happen
The water will move into the cell by osmosis and the cell will expand.
As the plant cell is expanding because of the solution is dilute (osmosis) what will happen
The cell wall will prevent the plant cell from bursting instead the cell will become swollen. Scientists call this TURGID.
If we place a plant cell into a concentrated solution then the water moves out of the cell by osmosis causing it to?
Shrink. This is called FLACCID
What’s the difference between diffusion and active transport
Diffusion:
Particles move down the concentration gradient
Diffusion does not require energy from respiration
Active transport:
Particles are moved against the concentration gradient
Requires energy from respiration
What’s the independent variable
Concentration
What’s the dependent variable
Change in mass
What’s the control variable
Volume of solution, temperature, time, Surface
Why do plants need magnesium
To make chlorophyll in their leaves
Why do plants require ions
Plants need ions for healthy growth
What is glucose
Sugars
What are sugar molecules used for
Sugar molecules are used for cell respiration
How does active transport allow mineral ions to be observed
Active transport allows mineral ions to be absorbed into plant root hairs from a very dilute solution in the soil
How does active transport allow sugar molecules to be absorbed
Active transport allows sugar molecules to be absorbed from lower concentrations into the gut into blood which has a higher sugar concentration
As organisms get larger What happens to the surface area and volume ratio
It gets smarter
cells on the surface get enough oxygen by…
Diffusion
Not enough oxygen can diffuse into the cell in the center of the organism. why?
They are too far away from the surface.
What are gills covered in
Large filaments
What do filaments do
It’s where gases pass in an out of the blood
How does the oxygen water pass through a fish
The oxygen water passes into the mouth where it flows over the gills where the oxygen is transported into the bloodstream
Explain how gills in fish are adapted for their exchange materials
Deoxygenated blood passes into the filament.
Oxygen diffuses from the water into the blood.
Oxygenated blood returns to the body
What do filaments give the gills
Massive surface area.
Filaments also have a thin membrane. What does a thin membrane provide
It provides a short diffusion
Filaments have an efficient blood supply to take the oxygenated blood away. what does this ensure
It ensures that the concentration gradient is always high
What is the equation for percentage change
% change = change in the value / original value x 100
When water moves in to the cylinder it’s gains mass. How does that happen? (Required practical)
By osmosis
In a concentrated sugar solution the cylinder loses mass as..
The water moves out by osmosis
If the line crosses the X axis there is no change in mass why is that?
That is because the concentration outside the cell is the same as the concentration inside the cell so no overall osmosis takes place
What are root hair cells specialized for
Absorbing water and minerals
Why are long hairs of the root hair cells important for the plant
It gives the plant a big surface area for absorbing water and minerals ions from the soil
Explain the gas exchange in lungs
The alveoli are where gas exchange takes place they have a
large surface area
moist lining
Thin walls
good blood supply
Explain villi in the small intestine
Millions of villi line in the small intestine increasing the surface area to absorb more digested food
they are a single layer of cells with a good blood supply
Explain the gas exchange in plants
The surface of leaves is flattened to increase the surface area for a more gas exchange by diffusion
oxygen and water vapor diffuse out of the stomata
guard cells open up and close the stomata controlling water loss
