Topic 2 Flashcards
What are the role of goblet cells
They produce mucus
What is the role of the mucus
It traps any dust,mucus and microorganisms found in our airways
How is mucus removed
It’s moved by waves of beating cila
Why is it hard for mucus to be moved in sufferers of cystic fibrosis
The mucus had little water in it so it’s very sticky
Why are low levels of oxygen created in mucus with people who cf
Oxygen diffuses to slowly through mucus
Epithelial cells use up more oxygen in cf patients
How are lung infections common with suffers of CF
As anaerobic conditions are created in the lungs due to low oxygen levels which enables harmful bacteria to thrive
How can white blood cells cause the mucus to be sticky
As when they break down they release DNA causing mucus to be even sticker
Explain how the lungs are adapted for gas exhahgrv
Large surface area for alveoli
Numerous capillaries good blood supply, maintains the concentration gradient, ventilation of lungs maintains the concentration gradient
Thin walls of capillaries and alveoli short distance between alveoli to travel
What are the 3 properties of gas exchange
Surface area
Concentration gradient
Thickness of gas exchange surface
Explain the relationship between surface area and rate of diffusion
They are directly proportional so as rate of diffusion increases so does surface area
Explain the relationship between concentration gradient and rate of diffusion
They are directly proportional so the greater the concentration gradient the faster the rate of diffusion
Explain the relationship between thickness of gas exchange surfaces and rate of diffusion
They are inversely proportional the thicker the surface area the slower the diffusion
What is fick law
Surface area*difference in concentration gradient
/
Thickness of gas exchange surface
What is diffusion
Net move of particles from an area of low concentration to an area of high concentration along a concentration gradient
How are concentration gradient mainted
By cells continuously using substances they have absorbed and producing waste products from them
What happens to organisms when they get larger
Their surface area per unit volume diminishes
Why can’t larger organisms rely on their general body for diffusion
As it’s too slow and the distance between cells is long
Describe why someone with cf will have breathing issues
Sticky,vicious mucus is produced
This mucus blocks the movement of air in bronchi.
Reduce gas exchange surface as reduces surface area for alveoli
Anaerobic conditions creating as a result of mucus leaves lung vulnerable to infection
The lung elasticity damaged as mucus makes it harder to breath out air
What do all amino acids contain
Amine group
Carboxylic acid group
Hydrogen
Residual group
What examples of protein are their in the body
Enzymes
Hormones
Antibodies
What is the primary structure of an amino protein
The sequence of amino acids in a polypeptide chain
What is the reaction called when two amino acids combine and what is the bond produced called
The reaction is called s condensation reaction and peptide bond is produced and water is released
How do secondary structures form in proteins
When in amino acids the polypeptide chains interact and coil up and fold
What are the two things formed in secondary structures
A helix
B pleated sheets
What is alpha helix
When hydrogen bonds form between the negative carboxylic acid and the positive amine group
What are beta plated sheets
When amino acids fold back on themselves and hydrogen bonds form linking them together
What is the tertiary structure of a protein
When the polypeptide chain folds to make a 3D shape which is held by chemical bonds between r groups
What are the 3 types of bond that can form between r groups in proteins
Hydrogen bonds
Ionic
Disulphide covalent bonds
When is a molecule described as a protein
When it’s 3D structure is functional
What is Quanternary structure
When the protein had more than one polypeptide chain
What are the two types of protein
Globular
Fibrous
Give characteristics of globular proteins
The polypeptide chain is folded into a spherical compact shape
They are soluble as they contain hydrophilic side chain
Give some characteristics of fibrous proteins
They remain as long chains that cross linking polypeptide chains which gives them strength
They are insouble proteins and are used as structural molecules
What problems does CF create in persons digestive system
The sticky mucus blocks the pancreatic duct so digestive enzymes can’t be released
Causes damage to the pancreas
Can cause diabetes due to enzymes damaging insulin producing cells
Malabsorption syndrome in which the rate of digestion is reduced as not all nutrients are absorbed
What are enzymes
Biological catalysts and globular proteins that speed up rate of reaction
Give 3 theories that explain the effect of enzymes active site
Lock and key theory
Induced fit theory
Activation energy
What is the lock and key theory
Substrate molecules bind into an active site as they have a complementary shape they produce an enzyme substrate complex in which they form a temporary bond
What are catabolic reactions
When enzymes break down larger molecules into smaller molecules
What are anabolic reactions
When enzymes build up reactions
How do u work out intial rate of reaction
Change in y
Change in X
What is activation energy
The amount of energy needed to break bonds to start a reaction
What is the structure of a membrane
Two layers of phospholipids which contain fatty acids
What is the phospholipid structure
Two fatty acid tails phosphate heads that are hydrophilic tails and the tails are hydrophobic
What two arrangements can phosphate lipids form
Bilayer
Micelles
Why do phsolipids form a bilayer
As it’s the most stable arrangement the head comes in contact with water tails face away
What are micelles and why isn’t the favoured arrangement
When they arrange themselfves in spherical clusters but it’s to bulky to fit
What things are found on a cell surface membrane
Glycoproteins
Glycolipids
Proteins
Cholesterol
What is the fluid mosaic model
The arrangement of cell membranes and that some proteins have the ability to move around and move freely
Name ways substances transport across a memebrane
Osmosis Diffusion Active transport Endocytosis Exocytosis
What is diffusion
The net movement of ions from an area of high concentration to a region of lower concentration
What is facilitated diffusion
When polar molecules or ions larger than co2 need to cross the membranes with the help of carrier proteins and they go through channel proteins
In facilitated diffusion how the carrier proteins carry molecules
The ion or molecule binds onto a specific site in the protein which makes it change shape
What is osmosis
The net movement of water molecules from an area of solution with lower concentration of solute to a solution with a high concentration of solute through a partially permeable membrane
What is active transport
Movement of substances against a concentration gradient which requires energy
How does active transport work
The substance to be transported binds on to a carrier protein
A phosphate by hydrolysis is removed from ATP from ADP which becomes hydrated and a lot of energy is released as a result of the bond formed
This causes the shape of the carrier protein to change and the substance is released
What is exocytosis and how does it work
When substances like proteins and polysaccharides are released from the cell
The cell membrane is fused with vesicles and they transport substances out of the cell
What is endocytosis
This is when substances are taken into the cell by vesicles
When theirs excess water in the mucus how is it released
The sodium pump pumps sodium ions outside the cell into the basal end into the tissue fluid
Due to an electrical created as a result of this cl ions go into the tissue fluid via a diffusion
Water via osmosis diffuses into the tissue fluid from the basal membrane due to the increase in solute concentration
The solute concentration in the basal membrane(epithelial cell)increases as a result and water from the mucus diffuses into the epithelial cell
What happens where their is to little water in the mucus
Cl ions are secreted into the mucus and they go via CFTr channel
The CFTr channel protein prevents the sodium pump from pumping sodium ions so they build up in the mucus
Due to increase in solute level water from the tissue fluid water diffuses into the mucus making to more viscous
What is wrong with people with cf Cftr protein
It’s not present or doesn’t function properly
Explain why people with Cf lungs can’t regulate water in mucus
Their cftr protein isn’t functioning properly
Meaning it can’t regulate the sodium channel properly so more sodium ions travel through into tissue fluid in which a electrical gradient is created so cl ions go from the mucus into epithiel cells into the tissue fluid
Due to the higher solute level in the tissue fluid water via osmosis is continuously drawn out of the mucus into then tissue fluid making mucus sticky
What is induced fit theory
That a substrate will cause the active site of a enzyme to change so it can fit in
What type of nucleic acid is DNA
deoxyribosenucleic acid
What are 3 molecule are found in mononucleotides
a deoxyribose
A phosphate group
Organic base with nitrogen
What are the bases in DNA molecules
Adenine
Guanine
Thymine
Csytine
What base pair are complementary and what bond forms between them
A and T
C and G
Hydrogen bonds
What reaction causes between mono nucleotides and what bond forms between two nucleotides
Condensation reactions occur between a sugar of one nucleotides and a phosphate group of another
It’s forms a phosphodiester bond
What are the differences between RNA and DNA
RNA contains a ribose sugar not deoxyribose
RNA contain a uracil base that replaces the thymine
RNA can leave nucleus
RNA has one strand and DNA has two strands
Give the names of RNA involved in protein synthesis
Messenger RNA
Transfer RNA
Ribsomal RNA
Describe what happens in transcription
RNA polymerase causes hydrogen bonds between bases to be exposed as the DNA molecule unwinds
The exposed bases on the DNA template strand pair up with free RNA nucleotides from the nucleus and the mrna forms alongside the DNA template strand
RNA polymerase creates phosphodiester bonds between the adjacent mrna nucleotides forming the mrna
Then it’s released through nuclear pore and exits the nucleus
What is the template strand
The Dna strand that the mrna is copied from
What is the role of tRNA and describe some of its features
It transfers amino acids to the ribosomes and it has a anticodon that is complementary to the mrna codon
Describe the process of translation
The mrna on the ribosome has its first base exposed a tRNA with a complementary is attracted to it and forms hydrogen bonds with it
The next codon on the mrna is exposed and it attracts another tRNA which is carrying a amino acid and it to binds on to the codon on the mrna
The amino acids that are held in place forms peptide bonds with one another and it occurs as a result of a condensation reaction
The first tRNA will return back to the cytoplasm to collect another amino acid and the process continues until a stop codon is reached which results in the polypeptide chain to stop growing and it detached from the ribosome
What is meant by the genetic code being degenerate
It means that several genetic code can code for the same amino acid
What is meant by the genetic code being non overlapping
It means that the codes are adjacent to one another and that they don’t overlap
Outline the steps in DNA replication and state what it’s called
DNA polymerase causes the hydrogen bonds between DNA to break causeing the DNA strand to unravel
Alongside each single strand of DNA free DNA nucleotides line up and hydrogen bonds form between there bases DNA polymerase links the adjacent nucleotides together via condensation reaction resulting in phosphodiester bonds forming between them
It’s known as semi conservative replication as it contains an old DNA strand and a new one
Describe the procedure in meelson and stahl experiment
They used DNA from escherichia bacteria which had grown in a medium which contained only a heavy type of nitrogen
They then put the bacteria in a medium that had nitrogen 14(so it had heavy and light nucleotides)
They allowed the bacteria and DNA to divide and replicate they then extracted and centrifuged the DNA after
What were the initial findings in melson and stahl experiment and what do after
They found just a middle band meaning they could discount the conservative theory of DNA replication
So they let the DNA undergo to more rounds of replication.
After the second round of replication what did melson and stahl find
They found two bands in the middle of the tube a light and medium band which supports semi conservative replication as it shows that a new DNA strand is made from both old and new strand
What types of mutations can take place in DNA
Mutation
Deletion
Insertion
Substitution
What is the locus
It’s the position at which two copies of a particular gene are located on two pairs of chromosomes
What are alleles
They are alternative forms of genes
What is the genotype
This is all the alleles that make up a persons genetic make up
What is a homozygous genotype
When a person has 2 identical copies of an allele for a gene
What is a heterozygous genotype
When a person has 2 different copies of an allele for a gene
What is a recessive allele
It needs two identical copies of the allele to produce a phenotype
Not expressed when there’s a dominant allele
Needs 2 alleles in order to be expressed
What is monohybrid inheritance
When a characteristic is only controlled by one gene
What is the purpose of genetic screening
It’s used to confirm the results of genetic testing and identify carriers
What is a dominant allele
Only needs one copy of an allele to produce a phenotype
Give 3 examples of prenatal testing
Chronic villus sampling
Amniocentesis NIPD
What happens in aminocentesis
It’s the insertion of a needle into the amniotic to collect fetal cells that have fallen of placenta and fetus
It occurs 15-17 weeks into pregnancy
What happens to in CVs
Insertion through abdomen wall or vagina to collect sample of placenta tissue
Happens in 8-12 weeks into pregnancy
What is the issue with both amniocentesis and chronic villus sampling
They carry a risk of miscarriage
1% risk of miscarriage form amniocentesis
1-2% risk of miscarriage for cvs
What is NIPD
It’s analyses DNA fragments in mothers bloods
Doesn’t require insertion of needle so it’s no risk of miscarriage
What happens in PGD
IVF is used to create embryos that are tested,the cells in the embryos are tested via genetic screening then it’s decided wheather or not to place In the uterus
What is the issue with PGD
IVF is expensive and stressful and low success rate
What is activation energy
The amount of energy needed to break bond to start a reaction
What are catabolic reactions
Enzymes break down larger molecules into smaller molecules
What are anabolic reactions
When enzymes build up reactions
Give differences between globular and fibrous proteins
Globular-soluble,compact 3D shape,enzymes,hydrophilic
Fibrous-insouble,straight chains,mainly secondary structure,hydrophobic
What was the issue with the original 3 layer protein sandwich
It didn’t allow for phosphate head to come in contact with water
It allowed for hydrophobic amino acids to be kept in and have contact with water
Give examples of evidence that support the fluid mosaic model
Change in interpretation of electron micrograph
Experiments showing two types of proteins
Human and mouse cell experiment
Freeze fracture
What things comprise a cell membrane in accordance to the fluid mosaic model
Phosplipid bilayer
Glycoproteins
Glycolipids(lipids with polysaccharides attached
What is incomplete dominance
When the trait from a dominant allele isn’t completely shown over the trait produced by a recessive allele,both alleles influence phenotype
How does improvements in electron micrograph interpretation provide evidence for the fluid mosaic model
The new evidence states that the phosphate heads are at darker regions or the membrane and that they are more electron dense and the lipid tails were at the lighter parts of the membrane
Suggest why phosphate heads are at the darker edges of the membrane
Due to the polar nature of the phosphate head
State what experiments have shown about proteins in the fluid mosaic model and how they support the model
Experiments show that there are two types of proteins
Some which can be dissociated from the membrane by ionic strength(easily dissociated)
Other proteins in the membrane which are harder to dissociate
Supports integral(they are fully embedded in the phoslipids and peripheral proteins which are loosely attached
Describe the procedure with the mouse and human cell and state how it supports the
Fluid mosaic model
They marked proteins in each cell and then fused them together after 40 mins they found that the proteins had intermixed
Supports the model as the only way they could have achieved this was by diffusion through the membrane showing that it’s fluid
What did freeze fracture show about the fluid mosaic model
The membranes were frozen and split along weak points between the lipid layer
Using electron microscopy they found a mosaic like surface with lipid tails along with larger proteins scattered among them
What are the functions of glycoproteins and glycolipids
Helps in cell to cell recognition
Glycolipids aid in receptors
What do both endocytosis and exocytosis require
ATP
Why are membrane more fluid when they have more unsaturated fatty acids
They contain a double bond that means they have a kink in there chain so they don’t pack close together
What is the role of cholesterol in the membrane
They are between phospholipids and it mains fluidity
State how enzymes can reduce activation energy
The charged groups in the enzyme and substrate interact causing the bonds in the substrate to change and distort
Which assist in bonds breaking or making
Describe the structure of collagen
3 polypeptide chains that are cooled tightly around one another
Every third amino acid has a small R group
Chains are held by covalent cross links
Used to function as support tissue
