Bio 5: Responding to the environment Flashcards
Tropism
Directional growth response in which the direct if the response is determined by the direction of the external stimulus
Plant growth regulators
Travel by active transport, diffusion, mass flow in phloem sap, or xylem vessels
Auxin
Promote: cell elongation
Increase wall stretchiness, hydrogen ion into cell wall promoted, lowers pH, expansins loosen walls, making them less rigid, allows water to expand.
Inhibit: growth of side shoots, leaf abscission
Cytokinins
Promote: cell division
Inhibits: senescence
Gibberellins
Promote: seed germination, growth of stems
Abscisic acid
Promotes: stomatal closure when stressed
Inhibits: seed germination and growth
Ethene
Promotes: fruit ripening
Apical meristems
Located at tips or apices of roots and shoots
Lateral bud meristems
Found in buds, give rise to side shoots
Lateral meristems
Found in a cyclinder near the outside of roots and shoots, responsible for widening
Intercalary meristems
Located between nodes
Apical dominance
Breaking the apex of a plant off, it starts to grow side branches from the lateral buds.
Abscisic acid inhibits bud growth, high auxin keeps abscisic acid high, when cut off auxin drops, and so does abscsic acid, Buds grow
Cytokinins promote bud growth, auxin makes shoot a sink, causing it all to go there, no auxin, spreads cytokinins more evenly.
Commercial uses: Auxins
- Encourages root growth
- Treating unpollinated plants can cause growth of seedless fruit
- Herbicides to kill weeds
Commercial uses: Gibberellins
- Delay senescence in citrus, extending life
- Elongate apples
- Grows grape stalks, allowing bigger grapes
- Speeds up starch into maltose for beer
Commercial uses: Cytokinins
- Delay senescence in leaves
- Tissue culture for mass production
Commercial uses: Ethene
- Speed up ripening
- Promotes fruit drop
Cerebrum
Largest part of the brain. Responsible for thought, imagination and reasoning.
Cerebellum
Controls coordination of movement and posture
Hypothalamus
Controls the autonomic nervous system and endocrine glands
Medulla oblongata
Controls the action of the smooth muscle in the gut wall and controls breathing movements and heart rate.
Motor area
Involved in planning, control and executing voluntary movements
Sensory area
Any sensory process, for example touch or sight
Parietal lobe
One of four major lobes. Controls skin sensory (pain, temperature and touch)
Occipital lobe
One of four major lobes. Visual processing centre
Wernicke’s area
Area in the left hemisphere of the temporal lobe, which is involved in speak comprehension
Broca’s area
Region in the frontal lobe of the dominant hemisphere and is linked with speech production
Temporal lobe
One of four major lobes. Language comprehension, emotional responses and visual memories
Frontal lobe
One of four major lobes. Voluntary movement, predicting, consequences, good and bad , and similarities and differences.
Limbic system
Involved with instinct and mood. Controls basic emotions (fear, pleasure, anger) and drives (hunger, sex, dominance, care of offspring)
Somatic nervous system
Somatic motor neurones carry impulses from the CNS to the skeletal muscle, which are under voluntary control.
Most are myelinated.
Autonomic nervous system
Autonomic motor neurones carry impulses from the CNS to the cardiac muscle, smooth muscle in the gut and glands. This is involuntary.
Most aren’t myelinated.
Parasympathetic and sympathetic.
Parasympathetic
Most active in sleep and relaxation
Linked with ganglion with target tissue, vary in length
Post ganglionic neurones secrete acetylcholine
Effects: decreased heart rate, pupil constriction, decreased ventilation rate, sexual arousal
Sympathetic
Most active in times of stress
Linked with ganglion outside spinal cord, very short
Post ganglionic neurones secrete noradrenaline
Effects: increased heart rate, pupil dilation, increased ventilation, orgasm
Antagonistic pairs
Muscles working in pairs opposite to each other
Cartiliage
Pads where bones meet reduce friction as bones move
Synovial membrane
Produces synovial fluid
Synovial fluid
Lubricates the joint
Ligament
Holds bones together to prevent dislocation
Neuromuscular junction
Specialised synapse between the end of the motor neurone and the muscle fibre membrane adjacent to it
Myosin
The protein that forms the thick filament in muscle cells. This protein has head groups that form the cross bridges associated with muscular contraction
Actin
A protein found in muscle cells. It is the main component of the thin filaments.
Tropomyosin coils around actin, reinforcing it.
Troponin attaches to Tropomyosin.
Smooth muscle
Autonomic nervous system (involuntary)
- Wall of intestines: peristalsis (moves food along intestine)
- Iris of the eye: Controls light entering eye
- Walls of arterioles, uterus: regulation of blood pressure
Cardiac muscle
Atrial muscle, ventricular muscle and specialised excitatory and conductive muscle.
Made of made individual cells collected in rows, intercalated discs, action potentials and ions diffuse easily
Skeletal muscle
Muscle cells form fibres of around 100um in diameter, with several nuclei. Each fibre is surrounded by sarcolemma, a cell surface membrane.
It has many mitochondria, sarcoplasmic reticulum, number of myofibrils
Troponin
Three polypeptides
- One binds to actin
- One binds to tropomyosin
- One binds to calcium ions
Power stroke
- myosin head attaches to actin forming a cross bridge
- head group bends, causing thin filament to be pulled. ADP and P are released
- Cross bridge is broken, ATP attaches to myosin head
- Head moves backwards as ATP is hydrolysed to ADP and P. Now it can repeat along.
Calcium and muscles
Action potential arrives.
Calcium is released from the sarcoplasmic reticulum
Diffuse through sarcoplas, bind with troponin
Changes troponins shape, moving tropomyosin away from binding site.
Allows a cross bridge to form
Maintenance of ATP
- Aerobic respiration in muscle cells
- Anaerobic respiration in muscle sarcoplasm
- Transfer from creatine phosphate, phosphate group can be used
Fight or flight
- Pupils dilate
- heart rate and blood pressure increase
- Arterioles to digestive system and skin constrict
- Arterioles to muscle and liver dilate
- Blood glucose conc increases
- Metabolic rate increases
- Endorphins released
Innate behaviours
- Genetically determined
- Passed onto offspring
- Rigid and inflexible
- Patterns of behaviour are the same
- Unintelligent, organism has no sense of behaviour
Learned behaviours
- Determined by relationship between environment and organism
- Not passed onto offspring
- Can be altered
- Variety
- Intelligent
Reflexes
Escape reflexes, are involuntary and follows a pattern following a stimulus
Kinesis
Orientation based behaviour where the rate of movement increases when an organism is in unfavourable conditions. Non-directional
Taxis
Directional orientation behaviour. Direction of movement is in relation to the stimulus. Positive is towards the stimulus, and negative is away.
Fixed action pattern
A stimulus is required to initiate an instinctive behavioural response. This leads to mechanisms within the brain which makes a fixed action pattern.
Habituation
Animals learn to ignore certain stimuli because repeated exposure has resulted in neither a reward or punishment.
Imprinting
Young animals become associated with on another organism - usually the parent
Classical conditioning
Classical conditioning theory involves learning a new behavior via the process of association. In simple terms two stimuli are linked together to produce a new learned response in a person or animal. There are three stages of classical conditioning.
Operant conditioning
Using reward and punishment to create associations between things.
Latent learning
Explore surrounding and retain information
Insight learning
Based on ability to think and reason in order to solve problems. This is not based on any reflex.
Dopamine
Neurotransmitter and hormone
Increases arousal
Decrease inhibition
Five receptors DRD1-5 (coded by a separate gene)
DRD4
50+ variants of DRD4
Particular variant of DRD4 common in ADHD sufferers
Variant in those with more risky behaviour eg smoking and gambling
