Mock Exam Flashcards
2 factors which affect biodiversity
Deforestation reduces trees in a area in which animal use for shelter and food sources
Climate change melts icecaps Meaning polar bears don’t have their habitat
Name one feature of a mass transport system
All substances move in the same direction at the same speed
Why do large multicellular organisms have circulatory systems
Cannot obtain oxygen and nutrients or remove waste products through diffusion so require other means of transport
State two difference between arteries and veins
Veins have valves arteries don’t
Arteries small lumen. Veins large lumen
Name the 4 components of blood
Red blood cells
White blood cells
Platelets
Plasma
Name 3 substances transported in blood plasma
Oxygen
Carbon dioxide
Water
4 chambers of the heart
Left atrium right atrium
Left and right ventricle
State the function and importance of valves in the heart
Prevent back flow of blood which is important to prevent the mixing of oxygenated and deoxygenated blood
What are the 3 stages of the cardiac cycle
Diastole heart relaxes atria and ventricles fill with blood
Atrial systole atria contract forcing blood from the atria into the ventricles
Ventricular systole ventricles contract forcing blood from the ventricles to either the rest of the body of the lungs
What is active transport
Movement of molecules into or out of a cell from a region of lower concentration to a region of higher concentration against a concentration gradient.energy is needed provided by atp
What is osmosis
Diffusion of water across a partially permeable membrane passive no energy required
What is the function of channel proteins
Passive moving of polar molecules and ions down a concentration gradient through membranes
Describe the structure of the cell membrane
Arranged in a phospholipid bilayer
With hydrophilic head facing outwards and hydrophobic tails facing inwards
Presence of carrier and channel proteins which allow larger molecules to whether the membrane which can’t pass through diffusion
How are disaccharides formed
Two monosaccharides OH groups are close together and react forming a glycosidic bond between the two molecules
One one similarity and difference between amylose and amylopectin
Amylose is linear amylopectin is branched
Amylose has 1-4 glycocydic bonds amylopectin has 1-4 1-6 glycocyduc bonds
Both polysaccharides
Both used in energy storage
Why is water important for the body
Acts as a transport median for molecules to be transported
Acts as a coolant which helps preserve enzyme activity and prevent denaturing this is due to large amounts of energy required to break hydrogen bonds so a constant temperature is maintained
Name 3 treatments for heart disease
Antihypertensives reduce blood pressure
Statins reduce blood cholesterol levels
Anticoagulants reduce formation of blood clots
What makes up the primary structure of a protein
Sequence of amino acids held together by peptide bonds
What’s are start and stop codons
Start codon is the site where protein translation initiates
Stop codon marks the termination of the translation progress
What is the function of tRNA
Form of RNA which helps transport amino acids.
What are the 3 parts of a nucleotide
Sugar
Phosphate group
Base
State 3 ways exchange surfaces are adapted for efficient exchange
Large surface area-provides large area needed for exchange and overcomes limitations of SA TO V ratio in larger organisms
Short diffusion distance-distance substances have to move is shorter so the process is fast and efficient
Good blood supply-steeper the concentration the quicker diffusion takes place
What is Mutation
A random change in the sequence of bases in a DNA molecule
How is DNA different to RNA
DNA is much large than RNA
DNA is double stranded
RNA is single stranded
DNA is self replicating
RNA is replicated through transcription
How could mutation affect the function of a enzyme
Mutations could cause a different or faulty protein to be synthesised . For example, if the protein is an important enzyme, the specific substrate might not fit into the substrate binding site
What is biodiversity
The variety of living organisms present in a area
What is a placebo
A treatment which has so physiological effect used in clinical trials to eliminate human bias and ensure there is no psychological influence on results
Why are stem cells so useful
They can differentiate into multiple cells meaning they can be used in a range of treatment
Grow organs
What are the 3 types of stem cell
Totipotent stem cell can differentiate into any type of cell
Pluripotent stem cells can form all tissues but not while organism and are present in embryos(embryonic stem cells)
Multi potent stem cells can only form a range of cells within a certain type of tissue
What is a stem cell
A undifferentiated cell
What is genetic screening
Used to test for genetic disorders
Can be performer before and after impregnating
Increase risk of miscarriage
Ethical implications if parents choose to abort fetus
One ethical issue of genetic screening
False reading can lead to the abortion of someone who doesn’t have a genetic disorder
Can influence parents choice on whether to abort child
2 differences between light and electron microscopes
Light Both live and dead organisms can be viewed in a electron only dead ones can
Light microscope cheap and accessible
Electron expensive only owner by university and pharmaceutical companies
Inaccessible
Two differences between xylem and phloem
Phloem is bidirectional can travel up and down the plant
Xylem is unidirectional only travels up the plant cell
Xylem is star shaped phloem isn’t
What is a double blind trial
a type of clinical trial where neither the participants nor the researchers know which group is receiving the experimental drug and which is receiving the placebo
What is polygenic inheritance
a characteristic, such as height or skin color, that is influenced by two or more genes
Name a example of a cell,a tissue a organ and a organ system
Cell- muscle cell
Tissue -multiple muscle cells create muscle tissue
Organ made up of multiple muscle tissues such as bladder
Organ system-kidneys ureter bladder and urethra all parts of urinary tract
5 features of a prokaryotic cell
No nucleus
Circular dna
Organelles are non membrane bound
Smaller 70s ribosomes
Presence of plasmids
5 feature of a eukaryotic cell
Has a nucleus
DNA is linear
Both membrane bound and non membrane bound organelles
Larger 80s ribosomes
Associated with proteins called histones
3 functions of mitosis
Producing asexual offspring which is genetically identical
Growth and repair of damaged tissue
Name the 4 stages of mitosis
Prophase chromosomes condense and become more visible
Metaphase chromosomes line up in middle of cell
Anaphase sister chromatide s separated and chromosomes pulled by spindles to opposite sides of the cell ensuring 2 separated daughter cells
Telophase- new nuclear membrane forms around each of the new chromosomes and they unwind and become less compact
What stage of the cell cycle is dna replicated
Interphase
How are organisms classified
3 domain system either arches bacteria and eukarya
Then separated further into 5 kingdoms
Anamalia
Plantae
Fungi
Prokarytae
Protictista
What are the products of meiosis
4 genetically different daughter cells
Haploid nucleus
What is a gene locus
In genetics, a locus is a specific, fixed position on a chromosome where a particular gene or genetic marker is located
What is a meant by a linked gene
Linked genes sit close together on a chromosome, making them likely to be inherited together
What is a sex linked gene
Sex-linked genes are located on the sex chromosome. This means the sex of an individual affects which alleles they pass on to their offspring through their gametes. If the gene is on the X chromosome, males (XY), will only have one copy of the gene, whereas females (XX) will have two.
what is the primary structure of a protein
sequence of amino acids in a polypeptide chains
what is the secondary structure of proteins
hydrogen bonds form between the amino acids which make sit coil into a alpha helix or beta pleted sheet
what is the tertiary structure of a protein
more bonds from between amino acids creating a 3d structure between r groups
Explain the role of dna Ligase in dna replication
Joins sections of dna together
By forming phosphodiestrr bonds
Between phosphate and sugar
Differences between dna and rna
DNA contains deoxyribose
RNA contains ribose which are slightly different sugars
RNA uses uracil instead of thymine
DNA double strand rna single strand
How can a mutation affect a function of a enzyme
Changes primary protein structure which changes active site shape so substrate no longer fits
describe how mineral ions are taken up by root hair cells
mineral ions taken up by active transport through carrier proteins which uses atp
