Cell biology Flashcards
What is an organelle
Tiny structures which carry out specialised functions
what is the function of the nucleus and what cells can it be found in
controls cell activities and contains genetic material/ DNA
found in animal, plant and fungal cells
what is the function of the cell membrane and in what cells can it be found
controls entry and exit of materials to and from the cell. It is selectively permeable
found in all 4 cell types
what is the function of the cytoplasm and in what cells can it be found
the site of chemical reactions within the cell. It is a liquid that is made up of water with other substances dissolved in it.
It can be found in all 4 cell types
what is the function of the cell wall and in what cell types can it be found
provides support to the cell
made of cellulose in plant cells and different aterials in fungal and bacterial cells
found plant, bacterial and fungal cells
function of chloroplasts and in what cells can it be found
contain the green chemical chlorophyll and are the site of photosynthesis
only present in plant cells
function of vacuole and what cells can it be found in
a large fluid/ sap filled structure that provides support for the cell
found in plant and fungal cells
what is the function of the mitochondrion and what cells is it found in
the site of aerobic respiration
found in animal, plant and fungal cells
function of the ribosome and what cells is it found in
the site of protein synthesis
found in all 4 cell types
function of plasmid and what cell types is it found in
small circular rings if DNA that can be replicated and transferred between bacteria
found in bacterial cell
what is a stain
a colourful chemical that is used to make some parts of a cell more visible
what is a micrometre (um)
a unit of measurement equivalent to
1/1000th mm
what is diffusion
the movement of molecules down a conventration gradient from a higher to lower concentration
it is a PASSIVE process and DOESNT REQUIRE ENERGY
what is a concentration gradient
the difference in concentration of a substance that occurs between two solutions or two cells/ tissues with solution
2 reasons why cells need diffusion
to take in substances they need e.g glucose and oxygen for aerobic respiration
to get rid of waste substances e.g carbin dioxide which is produced during aerobic respiration
what is osmosis
the movement of water molecules fro a higher water concentration to a lower concentratuin through a selectively permeable membrane.
it is a PASSIVE process anf DOESNT REQUIRE ENERGY
what is an independant variable
the variable altered during a scientific experiment
what is a dependant variable
the variable being tested and measured during an experiment
what is a controlled variable
a variable that is kept the same during an experiment
what happens to plant cells when placed in distilled water
plant cells gain water by osmosis as there is a higher water concentrations outside the cell than inside the cell. Water moves into the plant cells by osmosis down a concentration gradient from hugher to lower water concentration, which causes an increase in mass. The plant cell becomes TURGID
what happens to a plant cell when placed in strong sucrose solution
plant cells lose water by osmosis as there is a higher water concentration inside the cell than outside the cell. Water moves out of the cell by osmosis down a concentration gradient from higher concentration to lower concentration causing a decrease in mass. The plant cell becomes PLASMOLYSED
what happens when red blood cells are placed in dilute solutions
they burst because there is a higher water concentration outside the cell, so thesolution moves into the cell and increases its mass, and because there is no cell wall for support, it bursts.
what happens when red blood cells are placed in a concentrated solution
cells shrink because there is a higher water concentration inside the cell.
Water will move by osmosis out of the cells and because there is no cell wall fro support, the cell will shrink
what is active transport
Active transport requires energy in the form of ATP for membrane proteins to move molecules and ions against the concentration gradient
What are the 2 molecules in a cell membrane
Protein molecules (larger)
and phospholipid molecules (smaller)
How do molecules move in passive transport
From high concentration to low concentration
How do molecules move in active transport
Lower concentration to higher concentration
How do molecules in passive transport move in relation to the concentration gradient
Molecules move down the concentration gradient
How do molecules in active transport move in relation to the concentration gradient
Molecules move against the concentration gradient
Does passive transport require energy
No
Does active transport require energy
Yes, ATP
Examples of molecules moved by passive transport
Oxygen, water, carbon dioxide
Examples of molecules moved by active transport
Sodium, potassium, iodine
Molecule needed by leaf cell for photosynthesis
Glucose
Appearance of a plant cell in a strong salt solution
Plasmolysed
The movement of molecules down a concentration gradient from higher to lower
Diffusion
The movement of water molecules from a higher concentration to lower concentration through a selectively permeable membrane
Osmosis
Appearance of a plant immersed in pure water
Turgid
Where is DNA (largest to smallest)
Nucleus, chromosome, gene. DNA
Why is DNA needed
Carries the code to make all living things, proteins
Shape of DNA
Double helix
What are the four bases of DNA
Adenine (A)
Guanine(G)
Thymine(T)
Cytosine(C)
What are the complementary base pairs
C-G
A-T
What does DNA form in the nucleus
Chromosomes
What is the significance of the sequence of bases in DNA
It determined the structure and function of the protein.
It determines the order of amino acids
Where does protein synthesis take place
Ribosome
What is the role of the messenger RNA
Takes a version of the genetic code from the nucleus to the ribosome (cytoplasm)
What are the 5 functions of proteins
(Think of the acronym)
Structural- form essential structural support to cells like the proteins in the cell membrane and collagen
Hormones- chemicals that are produced in one part of the body and carried int he blood to another part e.g insulin
Antibodies- made by white blood cells and they help fight against disease. They are specific to the infection they work against
Receptors- act as a binding site for molecules
Enzymes- biological catalysts that speed up the rate of cellular reaction. They are essential and processes like photosynthesis would occur to slowly without them
What is a catalyst
Substance which speeds up a chemical reaction without being used up
What is an enzyme
Speed up the rate of cellular reactions while remaining unchanged
What is an active site
The location on the enzyme where the substrate attaches
What is a substrate
The substance an enzyme works on
What is a product
What is made at the end of an enzyme-catalysed reaction
What is an enzyme/substrate complex
Substrates in enzymes active site and enzyme reaction taking place
What does it mean when the reaction is specific
The action of an enzyme into working on one substrate
What is a degradation reaction
Where a large molecule is broken down into smaller molecules
What is a synthesis reaction
Reaction where smaller molecules are joined to from a larger molecule
What does optimum conditions mean
There are certain conditions in which an enzyme works at its best (most active), these are optimum conditions elg temperature and pH
What is the working range
The range of values e.g temperature or pH’s at which an enzyme is working
What does denatured mean
An enzyme that has had the shape of its active site permanently changed due to high temperatures
Describe a degradation reaction
A substrate fits into the active site of an enzyme to form an enzyme substrate complex. The reaction takes place and smaller molecules are released from the active site. The enzyme molecule remains unchanged and is then reused
Describe a synthesis reaction
The substrate of 2 smaller molecules fits into the enzyme to form the enzyme substrate complex. The reaction take place and one larger molecule is released, the enzyme can then be reused as it is unchanged
What is HP COW and what type of reaction is it
Substrate- hydrogen peroxide
Enzymes catalase
Products- oxygen and water
Degradation reaction
What is SAM and what type of reaction is it
Substrate Starch
Enzyme- amylase
Products- maltose
Degradation
What is G1PPS and what is its reaction type
Substrate- glucose-1-phosphate
Enzyme- phosphorylase
Product- starch
Synthesis reaction
What is FLAG and what type of reaction is it
Substrate- fat
Enzyme- lipase
Products- fatty acids and glycerol
Degradation reaction
What is PPP
What type of reaction
Substrate- protein
Enzyme- pepsin
Product- peptides
Degradation reaction
What do enzymes make
Proteins
What is an antibody
Proteins that defend the body against disease
What is a receptor
Protein on the cell surface with a shape complementary to a hormone
What is genetic engineering
Genetic engineering involves taking genetic information from one cell and transferring it into another. These cells can be from different species of organism.
The process is also known as genetic modification
What are the 8 stages of genetic engineering
- Identify a section of DNA that contains the gene for making the desired protein from the chromosome
- Remove the required gene using an enzyme
- Collect bacterial cell and remove plasmid
- Open the plasmid using the same enzyme that was used for the gene
- Insert the gene in to the open plasmid and close using a different enzyme
- Insert the plasmid into a host bacterial cell to produce a genetically modified organism
- Grow the bacteria to have lots of bacterial cells containing the new gene to make the new protein
- Extract and purify the protein for use
5 uses of genetic engineering
Human growth hormone- a hormone produced by cells in the pituitary gland. Essential during childhood and adolescence to control growth and development.
Insulin- made by pancreas cells. Controls the level of glucose in blood
Blight resistant potatoes- a food crop which is resistant to a fungal disease which causes rotting
Tomatoes- genetically engineered to have a longer shelf life
Golden rice- genetically engineered to be yellow in colour and contains lots of vitamin A
Antibiotic resistance
An example of a gene that is naturally transferred from one bacteria to another
Plasmid
Small circle of bacterial DNA
Gene
A short length of DNA that has the information to make a single protein
Donor
Organism from which the genetic material is obtained for transfer to another species
Advantages of using micro organism
Easy to work with
Multiply quickly
Advantages of producing medicinal products by genetic engineering
Quicker process
Less allergic reactions
What sugar is the most common source of energy in living cells
Glucose
What is respiration
An enzyme controlled reaction by which we ergo stored in sugar is released
Show model of ATP
Adenosine- Pi-Pi-Pi
Last bind is the bind which must be broken to release energy
When is energy uptake
ADP+Pi-ATP
When is energy released
ATP- ADP+Pi
3 uses of ATP
Cell division, muscular contraction,
Synthesis of proteins
What is aerobic respiration, and equation
The release of energy from glucose in the presence of oxygen.
Glucose + oxygen —(enzymes)— carbon dioxide + water + energy
What is stage one of respiration
Glycolysis
No oxygen required
Takes place int he cytoplasm
Glucose
I
I. 2 ATP
I
2x pyruvate
In glycolysis glucose is borne down into 2 molecules of pyruvate in a series of enzyme controlled reactions. No oxygen is required. This stage yields 2 ATP molecules overall and takes place in the cytoplasm of the cell
What is stage 2 of alibis respiration
Breakdown of pyruvate
Oxygen is required
Takes place int mitochondrion
Pyruvate
I
I A large number of
I. ATP
Carbon dioxide+ water
If oxygen is present aerobic respiration takes place, each pyruvate is broken down into carbon dioxide and water, enough energy is released to yield a large number of ATP molecules
This stage is controlled by enzymes and takes place in the mitochondria
What is fermentation and where does is occur
The breakdown of glucose when oxygen is absent
Occurs in animal cells and yeast cells
Takes place in cytoplasm
Absence of oxygen
Glucose
I
I 2 ATP
I
Animal Yeast and
Cells Plant cells
Lactate Ethanol
And
Carbon
Dioxide
Fermentation in animal cells summary equation
Glucose —(enzyme)— lactate + energy
Fermentation in plant and yeast cells summary equation
Glucose—(enzymes)— ethanol + carbon dioxide + energy
what is a respirometer
a piece of apparatus to measure the rate of respiration
for example volume of oxygen consumed per minute by a living organism
how does the respirometer work
carbon dioxide given out by the earthworm is absorbed by the sodium hydroxide
oxygen taken in by the earthworm causes the volume of air in the enclosed system to decrease and the level of coloured liquid in the tube to rise
the level of coloured dye is measured at the start
after a set period of time, the change in the level of coloured dye is measured to show the volume of oxygen used.
how would a control tube be used in a respirometer
it will not have a living organism in it, but will have everything else, to show that it was the impact from respiring and nothing else in the boiling tube that was having an effect
will a glowing splint relight in a boiling tube with live peas or boiled peas
the flask with boiled peas as they will not respire and use up oxygen
how is sterilising fluid used in an experiment with peas
sterilising fluid is used to soak the boiled peas to kill any microorganisms that may respire and use up oxygen
when does limewater turn cloudy
when carbon dioxide is added
will lime water turn cloudy in a test tube with live peas or boiled peas
limewater will turn cloudy in the test tube with live peas, as when they respire, they will produce carbon dioxide
will the temperature increase in a vacuum flask with live peas or boiled peas
the temperature will increase in the vacuum flask with live peas, as they will respire and produce heat energy, so the temperature on the thermometer will increase
pyruvate
produced first when glucose is broken down
product of fermentation in yeast that makes beer fizzy
carbon dioxide
where does the second stage of respiration occcur
mitochondria
3 cellular activities that require energy from ATP
active transport
protein synthesis
cell division
number of ATP yield per glucose molecule from fermentation
2
other name for alcohol produced by yeast fermentation
ethanol
where the first stage of respiration and fermentation take place
cytoplasm
ATP yield per glucose molecule from aerobic repiration
large number
controls the series of repiration reactions
enzymes
made from pyruvate in animal cells if oxygen is unavailable
lactate
required for the second stage of respiration
oxygen
short term store of chemical energy
ATP
cells that produce ethanol and carbon dioxide when oxygen is not available
plant
energy rich molecule that is the substrate for respiration
glucose
produced during aerobic respiration but not fermentation
water
