which muscle causes a joint to bend

ATI TEAS 7

ATI TEAS Practice Science Test

1. Which muscle causes a joint to bend?

A. Cardiac
B. Extension
C. Flexor
D. Smooth

Correct answer: C

Rationale: The correct answer is C: Flexor. A flexor muscle contracts to bend a joint, such as bending the elbow or knee. Flexor muscles are responsible for flexing or bending a joint, while extensor muscles are responsible for extending or straightening a joint. Choice A, Cardiac, is incorrect as cardiac muscle is found in the heart and is responsible for pumping blood. Choice B, Extension, is incorrect as extension refers to the straightening or extending movement of a joint, which is opposite to bending. Choice D, Smooth, is incorrect as smooth muscles are involuntary muscles found in organs like the intestines and blood vessels, not directly responsible for bending joints.

2. Which of the following is a common characteristic of alkynes?

A. They have a triple bond between carbon atoms.
B. They are saturated hydrocarbons.
C. They contain only single bonds.
D. They are aromatic compounds.

Correct answer: A

Rationale: The correct answer is A. Alkynes are hydrocarbons characterized by at least one triple bond between carbon atoms. This triple bond sets them apart from alkanes, which only have single bonds, and alkenes, which feature at least one double bond. The presence of a triple bond makes alkynes unsaturated hydrocarbons. Choice B is incorrect as alkynes are unsaturated hydrocarbons, not saturated. Choice C is incorrect because alkynes contain at least one triple bond, making them different from compounds with only single bonds. Choice D is incorrect because aromatic compounds have a distinct cyclic structure with resonance stabilization, a feature not shared by alkynes.

3. What is the difference between a sensory neuron and a motor neuron?

A. Sensory neurons carry signals from sensory receptors towards the central nervous system, while motor neurons carry signals away from the central nervous system to muscles and glands.
B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
D. Sensory neurons detect light, while motor neurons detect sound.

Correct answer: A

Rationale: Sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing the brain to receive information about the external environment. On the other hand, motor neurons carry signals away from the central nervous system to muscles and glands, enabling the brain to control voluntary and involuntary movements. Choice B is incorrect because sensory neurons do not control muscles, and motor neurons control both voluntary and involuntary muscles. Choice C is incorrect as sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system. Choice D is incorrect because sensory neurons detect various stimuli such as touch, taste, smell, and sound, while motor neurons are not involved in detecting sensory stimuli.

4. Which of the following are the products of anaerobic respiration in humans?

A. Ethyl alcohol and CO2
B. Ethyl alcohol only
C. Lactic acid and CO2
D. Lactic acid only

Correct answer: C

Rationale: During anaerobic respiration in humans, lactic acid and CO2 are produced. Choice A, 'Ethyl alcohol and CO2,' is incorrect because ethyl alcohol is not a product of anaerobic respiration in humans. Choice B, 'Ethyl alcohol only,' is incorrect as ethyl alcohol is not a product of anaerobic respiration in humans. Choice D, 'Lactic acid only,' is incorrect because CO2 is also a product of anaerobic respiration in humans.

5. Which of the following cell organelles is the site of lipid synthesis?

A. smooth endoplasmic reticulum
B. ribosome
C. rough endoplasmic reticulum
D. Golgi apparatus

Correct answer: A

Rationale: The correct answer is the smooth endoplasmic reticulum. This organelle lacks ribosomes on its surface, unlike the rough endoplasmic reticulum, which is involved in protein synthesis. The enzymes present in the smooth endoplasmic reticulum are responsible for synthesizing lipids such as phospholipids and steroids. Choice B, ribosomes, are responsible for protein synthesis and not lipid synthesis. Choice C, rough endoplasmic reticulum, is involved in protein synthesis due to the presence of ribosomes. Choice D, Golgi apparatus, is responsible for modifying, sorting, and packaging proteins for secretion, not lipid synthesis.