Bio Flashcards
What occurs during expiration?
Passive process
- internal intercostal muscles contract, external relax
- ribs move down and in
- this causes the diaphragm to relax and push against the abdomen
- which decreases thorax volume
- this all cause pressure to increase, forcing air out of the lungs.
How is the alveoli adapted to be efficient at gas exchange?
- large surface area
- surrounded by a network of capillaries
- distance between air and red blood cells is short
- red blood cells slow when entering the capillaries
What occurs during inspiration?
Active process
- external intercostal muscles contract, internal relax
- ribs move up and out increasing thorax volume
- this causes the diaphragm to flatten
- this all cause pressure to decrease, drawing air into the lungs.
What are proteins used for in the cell surface membrane?
- Antigens
- Carrier proteins
- Channel proteins
What are Glycolipids used for in the cell membrane?
- Recognitions sites
- Add stability to membrane
- Help form tissues
What are glycoproteins used for in the cell membrane?
- Recognitions sites
- Help form tissues
What’s cholesterol used for in the membrane?
- Reduces lateral movement of other molecules
- Prevents leakage of water and dissolved ions out of cell
What are the 3 stages of the cell cycle?
Nuclear divison
Cytokinesis
Interphase
What are the two main cancer treatments?
- Preventing DNA replication
- Inhibiting metaphase by preventing the production of spindle fibres
Activation energy
Energy required to bring about a reaction.
Active immunity
Resistance to disease resulting from the activities of an individual’s own immune system whereby an antigen induces plasma cells to produce antibodies.
Active site
A group of amino acids that make up the region of an enzyme that the substate binds.
Aerobic
Free of oxygen
Allergy
The response the immune system has to an allergen
Antibiotic
A substance produced by living organisms that can destroy or inhibit the growth of microorganisms
Antibiotic resistance
The development in microorganisms of mechanisms that prevent antibiotics from killing them
Antibody
A protein produced by lymphocytes in response to the presence of the appropriate antigen.
Anticodon
Sequence of 3 adjacent nucleotides on a molecule of tRNA that is complementary to a particular codon on mRNA
Antigen
Molecule that triggers an immune response by lymphocytes
B cell lymphocyte
Type of white blood cell that comes from bone marrow. They produce antibodies as part of their role in immunity.
Biodiversity
Range and variety of genes, species and habitats within a region
Cardiac output
Total volume of blood that the heart can pump each minute.
Carrier protein
Protein on the surface of the cell that helps to transport molecules and ions across plasma membranes
Codon
Sequence of 3 adjacent nucleotides in mRNA that codes for 1 amino acid.
Coronary arteries
Arteries that supply blood to the cardiac muscle of the heart
Co-transport
Transport of one substance coupled with the transport of another across a plasma membrane in the same direction through the same carrier protein.
Countercurrent system
Mechanism by which the efficiency of gas exchange between surfaces is increased by having them flow in the opposite direction.
Crossing over
Process whereby a chromatid breaks during meiosis and rejoins to the chromatid of its homologous chromosome so that alleles are exchanged.
Cohesion
Attraction between molecules of the same type
Diastole
Stage of cardiac cycle where heart muscle relaxes
Differentiation
Process by which cells become specialised for different functions
Ecosystem
All the living and non-living components of a particular area
Endocarp sis
Inward transport of large molecules through the cell surface membrane
Exocytosis
Outward bulk transport of materials through the cell surface membrane
Gamete
Reproductive Cell that fuses with another gamete during fertilisation
Gene
Section of DNA on a chromosome coding for one or more polypeptides
Gene pool
Total number of alleles in a particular population at a specific time
Habitat
Place where an organism normally lives and which is characterised by physical conditions and the types of other organisms present.
Haemoglobin
Globular protein in blood that readily combines with oxygen to transport it around the body.
Homologous chromosomes
Pair of chromosomes, one maternal and one parter all with the same gene loci and therefore determine the same features. Alleles of the same gene may vary.
Human genome
Totality of the DNA sequences on the chromosomes of a single human cell
Immunity
Means by which the body protects itself from infection
Intercropping
Practice of growing 2 or more crops in close proximity usually to produce a greater yield on a piece of land
Interspecific variation
Differences between organisms of different species
Intraspecific variation
Differences between organisms of the same species
Locus
Position of a gene on a chromosome with DNA molecule
Lumen
Hollow cavity inside a tubular structure such as the gut or a xylem vessel
Lymphocytes
Types of white blood cell responsible for the immune response. They become activated in the presence of antigens, there are two types.
Meiosis
Type of nuclear division in which the number of chromosomes in each daughter cell is halved
Mesophyll
Tissue found between layers of epidermis sis an plant lead comprising of an upper layer of palisade cells and a lower layer of spongy cells.
Metabolism
All the chemical processes that occur in living organisms
Mitosis
Type of nuclear division in which the daughter cells have the same number of chromosomes as the parent cell.
Mutation
Sudden change in the amount of or the arrangement of the genetic material in the cell.
Palisade cells
Long, narrow cells, packed with chloroplasts that are found in the upper region of a leaf and which carry out photosynthesis.
Species
Group of similar organisms that can breed together to produce similar offspring
Stomata
Pores, mostly found on the lower epidermis of a leaf, through which gases diffuse in and out.
Plasmid
Small circular DNA found in bacteria
Systole
Stage in the cardiac cycle in which the heart muscle contracts
Tissue fluid
Fluid that surrounds the cells of the body, it’s composition is similar to that of blood plasma, except it lacks proteins. Provides nutrients to cells and removes waste products.
Turgid
A plant cell that contains the maximum volume of water it can, additional entry of water is prevented by cell walls, which stop further expansion of the cell.
Ultrafiltration
Filtration assisted by blood pressure
Water potential
Pressure created by water molecules, it is the measure of the extent to which a solution gives out water. The greater the number of molecules present, the higher the water potential.
What is the biuret test?
Tests for proteins
Add sodium hydroxide and dilute copper (II) sulphate solution.
Positive test is purple.
How do you test for lipids?
Add ethanol and water to form a white emulsion.
Role of lipids
Waterproofing
Sourced of energy
Insulation
Protection
Water acts a solvent for:1
Gases like oxygen and carbon dioxide
Wastes like ammonia and urea
Inorganic ions
Features of water
Transparent
Non compressible
Evaporates to cool organisms
Active transport
Movement of molecules or ions in or out of a cell from an area of low concentration to an area of high concentration using ATP or carrier proteins.
Facilitated diffusion
Diffusion of molecules using carrier proteins or channel proteins.
Osmosis
Passage of water across a selective permeable membrane from an area of high water potential to an area of low water potential.
Diffusion
Net movement of molecules from an area of high concentration to an area of low concentration until evenly distributed.
Explain the direct active transport of a molecule/ion across a plasma membrane.
- ion/molecule binds to receptor sites on carrier protein in plasma membrane
- ATP binds to protein from within the cell, creating ADP and Pi, causing the shape of the protein to change shape
- ion/molecule released into cell
- phosphate released from protein, to form ATP later during respiration, protein reverts to original shape.
Explain co-transport
- sodium ions are actively transported into the blood by the sodium-potassium pump, using carrier proteins.
- there’s a higher concentration of sodium ions in the lumen of the intestine than the epithelial cells so sodium ions diffuse across, down the concentration gradient, using carrier proteins
- now the ions contain glucose molecules which it takes into the blood.
Transcription
Making pre-mRNA using part of the DNA as a template.
What occurs during transcription?
- Enzyme separates strands on DNA in a region
- Base on template strand pairs w/ complementary base from pool in nucleus
- RNA polymerase joins the bases together to form pre-mRNA
- DNA is rebuilt as pre-mRNA is built
- DNA detaches upon stop codon
Why does splicing occur?
Pre-mRNA is too large to leave the nucleus
Explain the process of translation.
- Ribosome attaches to codon on mRNA
- tRNA w/ complementary anticodon comes and attaches to codon on mRNA
- next anticodon attaches to next codon, each anticodon carrying a specific amino acid which is bonded together to form a peptide bond
- tRNA returns to get more amino acids, stop codon causes polypeptide to detach.
When is directional selection more likely to occur?
When environmental conditions change.
When is stabilising selection more like to occur?
When environmental conditions remain the same
Atrioventricular valves
Between atrium and ventricle
Semi lunar
Between atrium and pulmonary artery
How do insects limit water loss
Spiracles
Waterproofing
Small SA:V ratio
How do plants limits water loss
Waxy cuticles
Hairy leaves
Stomata
What are the two structures of gills?
Gill filaments
Gill lamellae
How do gases move in and out of insects
Mass transport
Along a concentration gradient
Xylem
Plant tissue which transports water and miners ions from the roots, up the stem to the leaves. Consists of vessels make of lignin. Provides a mass flow system for transport.
Zygote
A fused male and female gamete, by fertilisation.
Contains two sets of chromosomes, paternal.
White blood cell
Found in the lymphatic system and blood. Exist in many forms, posses a nucleus and cytoplasm.
Virus
Extremely small particle, only capable of replicating once inside a living cell.
Consists of nucleic acid surrounded by a protein coat.
Classified as non-living.
Vesicle
Small sac in cytoplasm surrounded by a cell membrane.
E.g. Golgi apparatus
Vascular tissue
Type of tissue found in plant, consists of xylem and phloem.
Vein
Blood vessel which returns blood from the capillaries to the heart. Usually contain deoxygenated blood in mammals, except for the pulmonary vein.
Found in leaves in plants.
Uracil
Nucleotide base found in RNA. Pairs with an adenine-containing nucleotide on DNA during transcription.
Replaced by thymine in DNA.
Triplet code
Information on DNA and mRNA is carried by sequences of three neighbouring bases.
Transpiration
Evaporation of water from plant leaves through the stomata.
Translation
Process which occurs in a ribosome, where amino acids are joined to form a polypeptide. In protein synthesis, the process of transcription results in the formation of mRNA. This leaves the nucleus and becomes attached to the ribosome where translation occurs.
Transcription
RNA polymerase and proteins bind w/ DNA when a gene is switched on, this produced mRNA (first stage in protein synthesis). A DNA unwinds, a template strand is used to produce an mRNA molecule by complementary base-pairing.
Trachea
Tube leading to the lungs, before bronchi.
tRNA
Type of RNA used in assembling amino acids into the correct sequence during translation.
During the cell cycle, what is the DNA called after being replicated?
Chromatids
