Practise IB Biology HL C3.1 by tracing reflex pathways and explaining feedback control, endocrine signals, ventilation and plant responses.
177 questions in this syllabus scope, with question parts counted together.
117 papers analysed · Tagging incomplete
Though a single nerve cell does not think, millions of them organized as a brain result in thinking. What kind of property does thinking represent?
Anatomical
Adaptive
Extracellular
Emergent
Stomach ulcers are often caused by Helicobacter pylori infection. These bacteria attach to the cells of the stomach wall using flagella. They secrete ammonia that neutralizes the acid in the immediate vicinity of the bacterial cells.
The liver is a large, complex organ with many metabolic functions. Outline the role of the liver in regulating the levels of nutrients in the blood.
The diagram is a view of the human brain as seen from the left side.
On the diagram, label the cerebellum.
The graph shows the mean cerebellum volume from MRI scans in eight primate species arranged in order of increasing body mass.
The spinal cord is involved in the coordination of involuntary actions such as the pain reflex.
Where are synapses between sensory neurons and interneurons found?
The image shows the anatomy of the human ear.
Explain how sound waves arriving at the inner ear are processed.
What is the main role of nerves in human movement?
To cause muscles to stretch
To move joints
To transport pain signals that indicate muscle injuries
To stimulate muscle contraction
No public sample questions are available for this syllabus point yet.
Which is the effector in a pain reflex arc?
Skeletal muscle
Sensory nerve ending
Pituitary gland
Grey matter of spinal cord
The drawing shows a vertical section through the brain.
State a function of the cerebellum.
Jetlag occurs when the circadian rhythm of a person changing time zones is disrupted. For what reason might they have difficulty sleeping after sunset?
The hypothalamus is secreting too much melanin.
The pineal gland is not secreting sufficient melatonin.
The lack of sunlight inhibits the production of vitamin D.
The pituitary gland is secreting too much oxytocin.
An individual was presented with a stimulus resulting in the release of epinephrine. What was the most likely nature of the stimulus?
Sunset and the onset of darkness
An image of a close friend
The intake of glucose
A coach shouting to begin physical activity
The hypothalamus is a region of the brain with a wide range of regulatory functions.
Outline two regulatory functions of the hypothalamus.
1.
2.
Explain the control mechanism of the heart rate.
The effects of altitude on athletic performance were investigated in teams of soccer players while they were acclimatizing to an altitude of 3600 m above sea level. The study group consisted of players from Bolivia who normally lived at high altitude and players from Australia who normally lived at sea level. and concentrations in arterial blood were measured daily over a 12-day period. concentrations were measured as the percentage saturation of hemoglobin and concentrations were measured as partial pressure.
In the Australian players, the rate of ventilation increases initially with altitude.
Explain how the rate of ventilation is controlled in humans.
Fluids inside unicellular and multicellular organisms allow materials to be moved.
Outline how food is moved from the stomach to the large intestine.
No public sample questions are available for this syllabus point yet.
The image shows the response of a plant shoot to light exposure.
Before
After
Naturwissenschaften. 96. 1339-1354, Springer Nature. Available at https://link.springer.com/article/10.1007/s00114-009-0604-z.]
What facilitates this response?
I. Auxin efflux carriers are located on one side of the cell.
II. Auxin promotes hydrogen ion secretion.
III. Cell walls become acidified and cellulose cross links are loosened.
I and II only
I and III only
II and III only
I, II and III
What is/are the effect(s) of auxin in plants?
I. Increasing the rate of cell elongation in stems
II. Changing the pattern of gene expression in shoot cells
III. Detecting the direction of light
I only
I and II only
II and III only
I, II and III
What correctly describes the action of auxin in phototropism?
Auxin efflux carriers actively transport auxin in and out of cells.
Auxin promotes hydrogen ion secretion into the cytoplasm.
Auxin efflux carriers are positioned in the plasma membrane on one side of the cell.
Auxin breaks beta-glucose links in the cell wall.
Expansin is a plant protein that loosens connections between cellulose fibres in plant cell walls, allowing growth. In what location would expression of the expansin gene be expected to be increased?
On the shaded side of a shoot being exposed to light
On the light side of a shoot being exposed to light
On the shaded side of a leaf that is transpiring rapidly
On the light side of a leaf that is transpiring rapidly
No public sample questions are available for this syllabus point yet.
Which chemical causes positive feedback to ensure rapid ripening of fruit?
Auxin
Cytokinin
Epinephrine
Ethylene
The diagram is a view of the human brain as seen from the left side.
On the diagram, label the cerebellum.
The graph shows the mean cerebellum volume from MRI scans in eight primate species arranged in order of increasing body mass.
Describe the use of fMRI to identify the role of the cerebellum.
