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LGS A-Level OCR Biology - Unit 5 - Plant and Animal Responses Part 4

Biology24 CardsCreated about 1 month ago

This deck covers key concepts from Unit 5 of OCR Biology, focusing on plant and animal responses, including muscle types, plant hormones, and the fight or flight response.

Why are endorphins released in the fight or flight response?

Wounds inflicted don't prevent activity
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Key Terms

Term
Definition
Why are endorphins released in the fight or flight response?
Wounds inflicted don't prevent activity
Why must plants be able to respond to their environment?
Cope w/ changing conditions | Avoid antibiotic stress
How does auxin cause cell elongation (2 marks)?
Loosens rigid cellulose framework | Osmotic uptake of water allows cell elongation
Why do cut plants w/ agar blocks w/ auxin placed on the rhs bend to the lhs?
Auxin produced at tip; Diffuses laterally to rhs; Cells on rhs exhibit greater elongation; Bending to the left
How does auxin act as a selective weedkiller?
Rapid cell elongation so plant grows too quickly; No extra lignified tissue; Stem collapses or loss of extra water from leaves
What happens when the apex is removed from a plant?
Once apex is removed, auxin production stops; Apical dominance is stopped; Lateral growth is not inhibited and lateral buds develop

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TermDefinition
Why are endorphins released in the fight or flight response?
Wounds inflicted don't prevent activity
Why must plants be able to respond to their environment?
Cope w/ changing conditions | Avoid antibiotic stress
How does auxin cause cell elongation (2 marks)?
Loosens rigid cellulose framework | Osmotic uptake of water allows cell elongation
Why do cut plants w/ agar blocks w/ auxin placed on the rhs bend to the lhs?
Auxin produced at tip; Diffuses laterally to rhs; Cells on rhs exhibit greater elongation; Bending to the left
How does auxin act as a selective weedkiller?
Rapid cell elongation so plant grows too quickly; No extra lignified tissue; Stem collapses or loss of extra water from leaves
What happens when the apex is removed from a plant?
Once apex is removed, auxin production stops; Apical dominance is stopped; Lateral growth is not inhibited and lateral buds develop
Types of muscle?
Skeletal (voluntary); Cardiac; Involuntary (smooth)
Voluntary (skeletal muscle)?
Striated; Multinucleate; Regularly arranged —> contraction in one direction; Attached to bone by tendon; Tubular; Nerves from peripheral, somatic (rapid)
Cardiac muscle?
Specialised striated (parallel myofibrils); Branched fibres; Uninucleated; Cross bridges allow simultaneous contraction; Dark bands - intercalated discs; Nerves from autonomic nervous system
Involuntary (smooth muscle)?
Non striated; Nerves from autonomic nervous system; No reg. arrangement - diff cells can contract in diff directions; Fibres are spindle shaped and uninucleated; Used in hollow organs (peristalsis)
Sarcolemma?
Plasma membrane that encloses bundles of muscle fibre
Why may the sarcolemma fold in?
Spread impulse throughout sarcoplasm; | Contract at the same time
Sarcoplasm?
Shared cytoplasm within muscle fibres
How are muscle fibres formed?
Fusion of several embryonic muscle cells - gap between adjacent cells would be a weakness (That’s why it’s multinucleate)
Sarcoplasmic reticulum?
Modified version of ER | Provides strength and stored Ca^2+
Protein filaments?
Myosin | Actin
Muscle organisation?
Muscle; Fascicles; Muscle fibres; Myofibrils; Protein filaments
Connective tissue?
Tendons
Light band (I)?
Thin actin held together by Z line
Dark band (A)?
Both actin and myosin; Entire length of myosin; Myosin held together by M line
M line?
Midpoint of myosin | Has no heads
Z line?
Found at the centre of each light band
Sarcomere?
Functional unit of muscle; From one Z line to another; Sub unit of myofibrils
Why is muscle considered a tissue?
Muscle fibre; Blood vessels; Nerves; Connective cells