March Mocks Flashcards
Organelle?
Tiny structures found withing cells
Cell?
The smallest unit of life
Tissue?
A group of similar cells working together to carry out a particular function
Organ?
A group of different tissues that work together to perform a particular function
Organ Systems?
A group of organs that work together to carry out a particular job
Fungi?
Unicellular or Multicellular, Eukaryotic Organisms
When they are Multicellular, a body called mycelium, made up of hyphae (thread-like structure) which contains a lot of nuclei
How do fungi feed?
Saprophytically
secret extracellular digestive enzymes onto decaying food material
Large molecules are digested into smaller molecules
Fungi cells absorb the smaller molecules
Protoctists?
Microscopic single-celled organisms
Examples of Protoctists?
Amoeba (pond water), have animal like features
Chlorella have chloroplasts and are more like plants
Bacteria?
Single-celled Prokaryotic
Some have chloroplasts –> some can Photosynthesis
Most bacteria feed off other living or dead organisms
Examples of Bacteria?
Lactobacillus
Pneumococcus which causes pneumonia
Viruses?
Non-living
Smaller than Bacteria
Wide variety of shapes and sizes
No cellular structure but have a protein coat and contain DNA or RNA
Only reproduce inside living cells
Examples of Viruses?
Tobacco mosaic virus –> causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplast
Influenza –> flu
HIV –> AIDS
Pathogenic Examples of Fungi?
tinea pedis –> Athletes foot
Pathogenic example of Protoctists?
Plasmodium –> Malaria
Differentiation?
The process by which a cell divides by mitosis into different specialised cells
Specialised Cell?
A cell with a particular structure of feature that allows it to carry out a particular job more effectively
Potential benefits of Stem Cells?
Offer a way of treating many different diseases caused by damaged cells
Potential risks of using stem cells?
Technique could be used illegally to produce human clones
If stem cells continue to divide in the body after they have replaces the damaged cells, they can result in cancer
Stem cells from one person are often killed by the immense system of another
Experiment to show Diffusion?
Pour 50cm3 of Iodine Solution into a beaker
Place a Viking Tubing (filled with Starch and Glucose inside of it)
After some time the solution outsides tests positive for glucose but negative for starch, because, the glucose is small enough to diffuse out of the tube into the solution from higher to lower concentration but the starch is too big
Factors affecting the rate of Diffusion?
Concentration gradient
SA: V
Distance
Temperature
Osmosis?
The movement of water from an area of higher water potential to an area of lower water potential across a selectively permeable membrane
Active Transport?
The movement of molecules from lower to higher concentration using a specific carrier protein and energy in the form of ATP
How are cells adapted for Active Transport?
Cells which carry out a lot of active transport have many mitochondria to release the extra energy (ATP) needed for the uptake
Balanced Diet?
One that contains all of the food groups in the correct amounts.
Carbs, protein, fat, vitamins, minerals, water and fibre
Source of Lipids?
What we use them for?
To provide energy, be an energy store, to protect organs and for heat insulation
Associated deffiecny with Lipids?
Feeling tired, too thin and at risk
Tests for Starch?
Add iodine solution
Orange Brown –> Blue Black
Testing for glucose?
Add benedicts solution
Heat up to (90)
Blue –> Red
Tests for Proteins?
Add sodium hydroxide and a few drops of copper sulphate
Blue –> Lilac
Tests for fat?
Crush with ethanol and then add water
White Emulsion will form
Enzymes?
Biological Catalysts which lower the activation energy of a reaction without actually being used up
How does Increasing Temperature increase the rate of reaction?
Increasing the Temperature
Increases KE
More Enzyme-substrate complexes are formed
Rate of reaction becomes faster
How does Increasing Temperature decrease the rate of reaction?
Increasing the temp above opt temps increases KE
active site 3D shape changes
No longer complementary to the substrate
Less Enzyme Substrate complexes are formed
Rate of Reaction will decrease
Digestion?
The breakdown of large insoluble molecules into small soluble molecules
What does Amylase do and where is it made?
Salivary Glands and released in mouth
Made in pancreas and released into the small intestine
Starch –> Maltose
What does Maltase do and where is it made?
Maltose –> Glucose
Made and found in the small intestine
What does Protease do and where is it made?
Protein –> A.A
Made and released in the stomach
Made in the pancreas and released into the small intestine
What does Lipase and where is it made?
Lipid –> Glycerol and fatty acids
Made in the pancreas and released into the small intestine
what pH do all enzymes in the small intestine have?
7
Absorption?
When the small, soluble molecules move from the small intestine into the blood
Assimilation?
When the absorbed molecules move into cells and become part of them or are used
Egestion?
Passing out undigested food as faeces via the anus
Peristalsis?
When food is squeezed through the gut by circular muscles which contract in waves
Adaptions of the Ileum for absorption?
It is very long and has many villi to increase SA
Many capillaries and a rich blood supply to increase the concentration gradient
The walls of the intestine are only one cell thick for a short diffusion pathway
Contains lacteals for lipid absorption
Adaptions of a villus absorption?
It is very long and has many villi to increase SA
Many capillaries and a rich blood supply to increase the concentration gradient
The walls of the intestine are only one cell thick for a short diffusion pathway
Contains lacteals for lipid absorption
Adaptions of epithelial cells for absorption?
Have microvilli which increase SA
Many mitochondria for more respiration for more energy for more active transport
Explain the process of Digestion?
Mechanical Digestion (Via Teeth) Amylase Present breaks down starch enzymes
Food moves down the Oesophagus via Peristalsis
The Food then enters the Stomach
(-Stomach pummels food with the muscular walls
-Produces the protease enzyme called pepsin which digests proteins into amino acids.
–> Stomach contains HCl to kill Bacteria and to provide optimum temp and pH for Pepsin)
Small Intestine Produces Proteases, amylase and lipase enzymes to completed digestion
This is where nutrients are absorbed out of Alimentary Canal into body.
The Large Intestine absorbs excess water in ileum from faecial matter
The Rectum is where the last part of the faeces is stored and when it is full it is released through the anus
What are three parts of the Small Intestine?
Duodenum
Jejunum
Ileum
How does the Duodenum Assist Digestion?
Where Majority of Digestion Takes Place
(Pancreatic Juice and Bile enters the duodenum via the Ampulla of Vater to assist and to enable absorption of molecules to occur)
Where is Bile Produced? and where is it stored?
Made in the liver
Stored in the Gall Bladder
What does the Pancreas do?
Produces enzymes such as lipase, amylase, protease which is released into the intestines (Also produces insulin)
What does Bile do?
Neutralises acidic contents of the stomach
Emulsifies Fat into tiny droplets
(Increases the surface area for which the lipase enzyme can work on)
Structure of DNA molecules?
2 Polynucleic strands, joined by complementary nitrogenous bases, coiled round in a spiral called a double helix
Which bases pair with each other?
A with T
G with C
Gene?
Section of DNA that codes for a protein
mRNA?
Messenger RNA-temporary copy of DNA
How does Transcription work?
Part of the DNA double helix unwinds and unzips so the 2 strands separate
Template (copy) strand
Bases are exposed along the template strand
Complementary RNA nucleotides line up along the template strand
The DNA ‘zips up’ again
This forms an mRNA molecule
The mRNA leaves the nucleus and enters the cytoplasm
2 stages of Protein Synthesis?
Transcription and Translation
Translation?
The mRNA molecule attaches to a ribosome
The first tRNA anticodon binds to the start codon on the mRNA strand
Another tRNA anticodon binds to the second codon on the mRNA strand
A bond forms between the two amino acids
The first tRNA molecule is released
More tRNA molecules arrive and add their amino acids to the chain, forming a protein
At the end of the mRNA molecule there is stop codon and the mRNA is released
Differences between DNA and mRNA?
DNA: Double Helix
RNA: Single Strand
DNA: BASE (T)
RNA; BASE (U)
DNA: DEOXYRIBOSE SUGAR
RNA: RIBOSE SUGAR
Allele?
A different form of the same gene
Genotype?
The alleles present in an organism
Phenotype?
The characteristic expressed in an organsim
Homozygous?
A genotype of the same alleles
Heterozygous?
A genotype of Opposite Alleles
Dominant?
A type of allele that is always expressed if it is present in the genotype
Recessive?
A type of allele that is only expressed if no dominant allele is present
Protein Synthesis?
DNA helix is untwisted and unzipped
mRNA nucleotides match to their complementary base on the strand
The mRNA nucleotides themselves are then joined together, creating a new strand of the original DNA
The template of mRNA strand moves to ribosomes
The bases on the mRNA are read in threes to code for an amino acid
The corresponding amino acids are brought to the ribosome by carrier proteins
These A.A connect together to form a protein
Mitosis stages?
The cell grows as organelles which grow and increase in number
Synthesis of Protein occurs
All 46 chromosomes are replicated
Energy Stores are increased
Chromosome lines up at the equator of the cell
Spindle fibres pull each chromosome of the ‘X’ to either side of the cells
Two identical cells form when the cytoplasm and cell membranes divide, each containing the same 46 chromosomes as the original cell
Meiosis formation?
The cells make copies of its chromosomes, so it has double the amount of genetic information
The cell divides into two cells, each with half the amount of chromosomes, giving the normal amount of 46 chromosomes
Each cell divides into two again to produce 4 cells, each with 23 chromosomes.
(Haploid)
Excretion?
the process of eliminating or expelling waste matter.
3 examples of Excretion?
Breathing, Sweating and Urination
What does Urea contain?
Nitrogen
Ultrafiltration?
Blood from renal artery flows through the glomerulus at high pressure
Pressure within the glomerulus is high
The high pressure causes water ions etc: to filter out of the glomerulus and enter the Bowman’s capsule
The membranes between the blood vessels in the glomerulus and the Bowman’s capsule act like filter,
big molecules like proteins and blood cells are not able to be squeezed out.
They stay in the blood
The filtered liquid is known as Glymerolus filtrate
Explain the process of Reabsorption?
As the filtrate flows through the nephron, useful substances are selectively reabsorbed into the blood
All the glucose at the Proximal convoluted tubule
The reabsorption of glucose requires AT
Sufficient Ions are reabsorbed
Sufficient amount of water is reabsorbed from the collecting duct into the blood by osmosis
Remaining water is excreted as urine
Inhalation?
Intercostal Muscles Contract
Ribcages move up and out
Volume of Thorax increases
Air pressure inside the thorax decreases
Air enters
How are Sperm cells adapted?
- Streamlined head and long tail to aid swimming
- Many Mitochondria
- Acrosome (to pof the head) has digestive enzymes which break down the outer layers of membrane of the egg cell
How are Nerve Cells adapted?
The axon is long, enabling the impulses to be carried along long distances
Having lots of extensions from the cell body means branched connections can form with other nerve cells
Nerve endings have many mitrochondria
How are Root Hair Cells adapted?
Large SA:V
Large Permanent Vacuole affects the speed of movement of water from the soil to the cell
Mitochondria for AT
How are Xylem Cells adapted?
Lignin –> Cells die
Cells (hollow and join end-to-end to form a continuos tube for water and mineral ions to travel through from the roots
Water molecules are attracted to each other by hydrogen bonding - creating a continuos column of water up the plant
Water evaporates creating a transpiration stream
Lignin strengthens the plant to help it withstand the pressure of the water movement
Lignin contains bordered pits, which are holes to allow specific areas for water and therefore minerals to enter the plant
Adaptions of Phloem Cells?
Cell walls form sieve plates when they break down
This allows the movement of substances from cell to cell
Mitrochondira
Types of Stem Cells?
Embryonic Stem Cells, Adult Stem Cells and Meristems in Plants
Embryonic Stem Cells?
Form when an egg and sperm cell fuse to form a zygote
Differentiates into any type of cell
Adult Stem Cells?
If found in bone marrow they can form many types of cells including blood cell
Meristems?
Found in Shoots and Roots
Dfuferentiate into any type of plant
Why do Pregnant people need more energy?
Energy Requirements will increase in order to support growth of the foetus
Energy needs also increase due to the extra mass of the baby
Adaptations Spongy Mesophyll for Gas Exchange?
Have lots of air spaces to allow gases to diffuse in and out of cells faster, as it increases the SA:V
Use of Waxy Cuticle?
Helps to reduce water loss by ecaporation and is a protective layer found at the top of the leaf
Use of Upper Epirdermis?
Very thin and transparent in order to let light in to the palisade mesophyll
Use of Palisade Mesophyll
Contains lots of Chloroplasts so that photosynthesis can happen rapidly
Lower Epidermis?
Contains guard cells and stomata
Ribs?
Bone surrounding the lungs to provide protection of internal organs
What is CHD?
When Coronary arteries supply blood to the heart the arteries become blocked.
This is due to a build-up of fatty plaques.
This can cause ischaemia which can eventually lead to a muscle death
Causes of CHD?
Poor Diet- increases cholesterol levels, which can increase the chance of fatty plaques building up.
High levels of salt can increase blood pressure which damages the blood vessels and increases the chances of fatty deposits building up
Smoking-
Nicotine causes narrowing of CA and increases Blood Pressure, which can increase the chance of a blockage in the CA
Stress-
Hormones produced in times of stress can increase blood pressure, which can damage the vessel walls
Explain the effect of pH on Proteases?
Optimum pH means that the active site is in the correct shape
When pH falls or rises from the optimum the shape of the active site changes-it Denatures
This occurs because the change in environmental causes BONDS within the enzyme to break, so enzyme unravels
This means that the substrate can no longer fit into the active site
Reaction rate falls as less substrate digested
Opt pH is pH 1.5 which is found in the Stomach
An enzyme called Protease can digest in this environment
Explain the effect of pH on Pepsin?
Optimum pH means that the active site is in the correct shape
When pH falls or rises from the optimum the shape of the active site changes
Describe an experiment you could carry out to compare the concentration of samples of plasma and glomerular filtrate?
Benedict’s
Heat
Red in High Concentration of Glucose
Orange/yellow-green in low concentration of glucose
control volume of samples
Cornea?
Transparent Outer Part of the Eye
It refracts light to each retina
Iris?
The coloured part of the eye that does not allow light to go through
What does the Iris do?
Controls how much light enters the eye
Lens?
Transparent, biconvex disc that attaches to ciliary muscles by the suspensory ligaments
What does the Lens do?
Focuses light onto the retina
Retina
contains light receptors
Accomodation of a near object?
Ciliary muscles contact
Suspensory Ligaments slacken
Lens fatter
More light refracted
Light converges on the retina
Accomodation of a Distant Object?
Ciliary Muscles relax
Suspensory Ligaments stretch
This allows the lens to become thin so the light is refracted less
Light converges on the Retina
How do Platelets work?
When a blood vessel is damaged platelets respond by releasing an enzyme which causes the formation of a fibrous protein called fibrin
Fibrin traps blood cells and forms a blood clot
Explain how Glucose is regulated?
Glucose levels controlled by the Pancreas
Detects levels of glucose as blood flows through (receptors)
Secretes Hormones
Insulin –> Lowers Blood Glucose Levels
OR
Glucagon–> Raises blood glucose levels
How does Insulin change blood sugar level?
Travels in blood stream to target cells (muscles and liver)
Causes cells to take up glucose
Some used in respiration (muscles)
Some stored as glycogen (liver)
Lowers blood sugar levels
How does Glucagon change the blood sugar level?
Travels in blood stream to target cells in liver
Glycogen broken down into glucose
Glucose released into blood
Raises Blood Levels
Use of Progestorone?
Maintains the uterus lining so that the fertilised egg can implant
Pros of a Bomb Calorimeter?
Oxygen for complete food combustion
food enclosed so less energy lost
insulation so less heat lost
lid so less heat loss
copper (good conductor) heats up water
stirrer distributes heat
why might it be better to use a larger volume of water in a calorimetry experiment (that is not in a Bomb Calorimeter)?
Less heat loss
Heats up slower
Smaller SA:V
How could someone improve an experiment that measures breathing rate?
Repeat
Measure Breathing rate during Excercise
Run at same Speed
Nervous Vs Endocrine System?
Neuro System:
Electrical
Nerve Cells
Very Fast
Short
Endocrine Glands:
Chemical
Hormones in bloodstream
Slower
Long
Affect of Light Intensity on Transpiration?
Increased Rate of Photosynthesis
More Stomata open to allow gaseous exchange
More Water can evaporate
Increased Rate of Transpiration
How does Temperature affect Transpiration?
The molecules move faster
Evaporation at a faster rate
Transpiration increases
Rate of Photosynthesis increases
More stomata are open for gaseous exchange
More water evaporates and the rate of transpiration increases
How to investigate the Rate of Transpiration?
Cut under water
Make sure it’s water tight
Make sure a singular bubble is there
Measure distance the bubble moves
Use ruler
Repeat
Phloem Adaptations?
Translocation
Many Organelles from the cells are removed so cell sap can move through
Many mitochondria in companion cells which provide the energy the cells require
Food substances can be moved in both directions, from the leaves where they are made for use, or from storage
Leaf Anatomy
See
Kidney System Anatomy
See
Eye Structure
See
Motor Neurone Diagram
See
