Search results for "Muscle Contraction"

Biology

CAIE2024

D [4] (c) Lambert‑Eaton myasthenic syndrome (LEMS) is a rare disorder of the neuromuscular junction. A person with LEMS produces antibodies that bind to the voltage‑gated calcium channels on the presynaptic knob. One symptom of LEMS is weaker muscle contraction. Suggest and explain why LEMS leads to weaker muscle contraction. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [4] [Total: 11] © UCLES 2024 (cid:300) (cid:300) (cid:207) (cid:224) (cid:266) (cid:202) (cid:190) (cid:243) (cid:288) (cid:215) (cid:180) (cid:294) (cid:237) (cid:242) (cid:200) (cid:273) (cid:245) (cid:220) (cid:207) (cid:257) (cid:298) (cid:252) (cid:197) (cid:292) (cid:266) (cid:283) (cid:223) (cid:274) (cid:251) (cid:292) (cid:183) (cid:179) (cid:258) (cid:277) (cid:215) (cid:258) 9700/42/O/N/24 [Turn over (cid:293)(cid:181)(cid:181)(cid:213)(cid:245)(cid:245)(cid:197)(cid:181)(cid:181)(cid:293)(cid:261)(cid:197)(cid:197)(cid:181)(cid:229)(cid:213)(cid:261)(cid:213) NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD PMT * 0000800000020 *

Question

Biology

CAIE2024

(a) Fig. 8.1 is a diagram of a motor neurone. X Y Z Fig. 8.1 (i) Name cell X and part Y. X ........................................................................................................................................ Y ........................................................................................................................................ [2] (ii) Name a type of cell that forms a synapse with structure Z. ..................................................................................................................................... [1] (b) Table 8.1 shows some of the events that occur during muscle contraction. They are not listed in the correct order. Table 8.1 event description of event A calcium ions diffuse out of sarcoplasmic reticulum B myosin heads bind to actin C sarcolemma depolarised D sarcomere shortens E calcium ions bind to troponin F T‑tubule system membranes depolarised G binding sites on actin exposed H myosin heads tilt I tropomyosin moves J troponin changes shape (cid:300)(cid:205)(cid:266)(cid:190)(cid:288)(cid:180)(cid:237)(cid:200)(cid:245)(cid:207)(cid:298)(cid:197)(cid:266)(cid:223)(cid:249)(cid:183)(cid:258)(cid:215) © UCLES 2024 (cid:300)(cid:224)(cid:201)(cid:244)(cid:207)(cid:292)(cid:238)(cid:289)(cid:221)(cid:247)(cid:261)(cid:229)(cid:191)(cid:298)(cid:184)(cid:179)(cid:293)(cid:258) 9700/42/O/N/24 (cid:293)(cid:181)(cid:197)(cid:277)(cid:181)(cid:277)(cid:229)(cid:213)(cid:229)(cid:277)(cid:213)(cid:197)(cid:197)(cid:213)(cid:197)(cid:277)(cid:277)(cid:213) NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD PMT * 0000800000019 *

Question

Biology

CAIE2023

When an impulse arrives at a neuromuscular junction, it stimulates a muscle fibre of striated muscle to contract. (a) (i) Outline the similarities in structure between a neuromuscular junction and a cholinergic synapse. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] (ii) The hydrolysis of ATP during muscle contraction releases inorganic phosphate (P). i Calcium ions (Ca2+) can combine with P in the sarcoplasmic reticulum to form insoluble i calcium phosphate. This may result in fewer power strokes occurring in sarcomeres. Suggest why calcium phosphate formation in the sarcoplasmic reticulum may result in fewer power strokes occurring in sarcomeres. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] © UCLES 2023 9700/43/O/N/23 PMT

Question

Biology

CAIE2023

(b) Adrenaline is a hormone that can affect muscle contraction. Adrenaline binds to G-protein-coupled receptors on T-tubule membranes. The cell signalling pathway that occurs in response to the binding of adrenaline is similar to the pathway that occurs in liver cells in response to the binding of glucagon. Fig. 7.1 is an outline of the cell signalling pathway of adrenaline. adrenaline receptor A T-tubule membrane activated ATP cAMP G-protein activates B cellular response including muscle contraction Fig. 7.1 Identify the molecules represented by A and B in Fig. 7.1. A .......................................................... B .......................................................... [2] [Total: 9] © UCLES 2023 9700/41/O/N/23 [Turn over PMT

Question

Biology

CAIE2023

(b) Adrenaline is a hormone that can affect muscle contraction. Adrenaline binds to G-protein-coupled receptors on T-tubule membranes. The cell signalling pathway that occurs in response to the binding of adrenaline is similar to the pathway that occurs in liver cells in response to the binding of glucagon. Fig. 7.1 is an outline of the cell signalling pathway of adrenaline. adrenaline receptor A T-tubule membrane activated ATP cAMP G-protein activates B cellular response including muscle contraction Fig. 7.1 Identify the molecules represented by A and B in Fig. 7.1. A .......................................................... B .......................................................... [2] [Total: 9] © UCLES 2023 9700/43/O/N/23 [Turn over PMT

Question

Biology

CAIE2023

When an impulse arrives at a neuromuscular junction, it stimulates a muscle fibre of striated muscle to contract. (a) (i) Outline the similarities in structure between a neuromuscular junction and a cholinergic synapse. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] (ii) The hydrolysis of ATP during muscle contraction releases inorganic phosphate (P). i Calcium ions (Ca2+) can combine with P in the sarcoplasmic reticulum to form insoluble i calcium phosphate. This may result in fewer power strokes occurring in sarcomeres. Suggest why calcium phosphate formation in the sarcoplasmic reticulum may result in fewer power strokes occurring in sarcomeres. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] © UCLES 2023 9700/41/O/N/23 PMT

Question

Biology

CAIE2022

( a) The contraction of striated muscle is explained by the sliding filament model. ( i) Describe what happens in the sarcomere when the myosin head releases ADP and inorganic phosphate ( Pi) . ........................................................................................................................................... ...................................................................................................................................... [1] ( ii) Explain the p rec ise function of ATP in the sliding filament model. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3 ] ( b) During contraction, muscles use up ATP very quickly. F or a short period of time, ATP can be resynthesised using creatine phosphate, as shown in F ig. 5 .1. ADP + creatine phosphate ATP + creatine Fig. 5 . 1 The creatine formed as a result of the resynthesis of ATP is converted to creatinine. Creatinine production in the body stays fairly constant. Creatinine becomes part of the glomerular filtrate during ultrafiltration in the kidney nephrons. ( i) Ultrafiltration requires a high blood pressure in the glomerulus. Explain how this high blood pressure is achieved. ........................................................................................................................................... ...................................................................................................................................... [1] ( ii) Name the main filtration barrier in the nephron that allows creatinine to pass into the Bowman’s capsule but stops red blood cells from passing through. ...................................................................................................................................... [1] © UCLES 2019 97 00/04/SP/22 [Turn over PMT

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