G.C.E. (A/L) Biology Grade 13 Genetics

Questions and Answers

What is the function of melanocytes in the skin?

Providing sensory perception

Producing collagen fibers

Regulating body temperature

Secreting the pigment melanin (correct)

Which of the following structures is NOT found in the dermis?

Sebaceous glands

Sweat glands

Hair follicles

Keratinocytes (correct)

How does the skin contribute to thermoregulation?

By contracting arrector pili muscles

By secreting melanin

By allowing heat loss through perspiration (correct)

By increasing blood flow to the epidermis

What type of connective tissue composes the dermis?

Areolar connective tissue Signup and view all the answers

Which of the following is a protective function of the skin?

Forming a barrier against microorganisms Signup and view all the answers

What role do fibroblasts play in the dermis?

Secrete collagen and elastic fibers Signup and view all the answers

What pigment can excessively accumulate in the fat layer and impact skin color?

Carotenes Signup and view all the answers

What type of cells in the skin can phagocytose foreign invaders?

Macrophages Signup and view all the answers

What is the primary function of the choroid in the eye?

Absorbing light after it enters the eye Signup and view all the answers

What is monocular vision primarily associated with?

Viewing a scene from a single angle Signup and view all the answers

How do humans typically achieve binocular vision?

By positioning both eyes in front of the face Signup and view all the answers

What advantage does binocular vision provide over monocular vision?

It enhances three-dimensional vision Signup and view all the answers

What is a key feature of binocular vision regarding visual fields?

The visual fields from both eyes overlap Signup and view all the answers

In which scenario might an individual experience difficulty with distance judgment?

When practicing monocular vision Signup and view all the answers

What role does the occipital lobe play in vision?

It processes visual stimuli from both eyes Signup and view all the answers

Why is binocular vision particularly important for judging an approaching vehicle's speed?

It provides a better assessment of distance and speed Signup and view all the answers

What is the primary function of sensory receptors?

To detect specific stimuli and convert them to action potentials Signup and view all the answers

Which of the following best describes sensory adaptation?

A decrease in responsiveness to a continuous stimulus over time Signup and view all the answers

What type of neurons are some sensory receptors classified as?

Specialized neurons that can detect stimuli Signup and view all the answers

What role do sensory receptors play in maintaining homeostasis?

They provide information about internal and external conditions Signup and view all the answers

What is the process called when sensory signal strength increases during stimulus conversion?

Signal amplification Signup and view all the answers

Which statement about sensory receptors is NOT true?

They only detect external stimuli and not internal conditions. Signup and view all the answers

In the context of sensory perception, what is the 'threshold level'?

The level of stimulus energy required for detection to occur Signup and view all the answers

Which characteristic is essential for a sensory receptor to function effectively?

It must convert stimulus energy into a membrane potential Signup and view all the answers

What is the primary purpose of the supplementary resource books prepared by the National Institute of Education?

To enhance the quality of education. Signup and view all the answers

Who contributed to the preparation of the supplementary resource books?

A combination of curriculum developers and subject experts. Signup and view all the answers

In what year was the new syllabus implemented that the resource books adhere to?

2017 Signup and view all the answers

What main benefit do the supplementary resource books provide to students?

They broaden understanding of the subject matter. Signup and view all the answers

Which educational body is responsible for creating the resource books?

National Institute of Education Signup and view all the answers

What type of subjects do the supplementary resource books cover?

Specific subjects from the G.C.E. Advanced Level syllabus. Signup and view all the answers

What approach do the supplementary resource books suggest for teachers?

Integrating these resources for effective learning activities. Signup and view all the answers

What is one key aspect of the resource books regarding the curriculum?

They are designed to be supplementary to the implemented syllabus. Signup and view all the answers

What is the typical range of resting potential in a non-conducting neuron?

-60 mV and -80 mV Signup and view all the answers

Which ion is found in higher concentration outside the neuron?

Na+ Signup and view all the answers

What primarily maintains the resting membrane potential in neurons?

Unequal distribution of ions Signup and view all the answers

Why does a neuron have a negative charge inside the cell at resting potential?

There are more potassium channels open than sodium channels. Signup and view all the answers

What is the primary role of potassium and sodium channels in a neuron?

To allow certain ions to pass based on their concentration gradient. Signup and view all the answers

Which ion contributes to the positive charge found outside of the neuron?

Sodium ions (Na+) Signup and view all the answers

In the resting state of a neuron, what happens to potassium ions?

They remain inside the cell at high concentrations. Signup and view all the answers

What effect does the selective permeability of the plasma membrane have on membrane potential?

It allows more potassium ions to flow out than sodium ions to flow in. Signup and view all the answers

Study Notes

General Overview

G.C.E.(A/L) Biology Resource Book is aimed at Grade 13 students, focusing on Animal form and function, specifically Genetics.
Developed by a collaborative team from the National Institute of Education, including curriculum developers, subject experts, and experienced teachers.
Aligns with the new syllabus implemented in 2017 to enhance understanding and teaching methods.

Nerve Impulses Generation and Transmission

Neurons maintain unequal distribution of ions, resulting in a voltage difference across the plasma membrane, known as membrane potential.
Resting potential typically ranges from -60 mV to -80 mV in non-conducting neurons.
Resting potential is maintained by:
- High K+ concentration inside the neuron and higher Na+ concentration outside.
- Selective permeability of the plasma membrane to K+ and Na+, with more open potassium channels contributing to the negative charge.

Sensory Receptors

Specialized structures that detect specific stimuli and convert energy into action potentials for sensory perception.
Types of sensory receptors include specialized cells, organs, or subcellular structures.
Characteristics include:
- Ability to detect stimuli at or above threshold levels.
- Conversion of stimulus energy into membrane potential.
- Connection to the nervous system.
- Signal amplification and sensory adaptation, where continuous stimulation decreases responsiveness.

Vision

Human eyes facilitate coordination for visual perception, with monocular vision (using one eye) providing limited depth perception.
Binocular vision involves both eyes for a comprehensive visual field, allowing better judgment of speed and distance.
The overlap of visual fields assists in creating a single image in the brain, critical for depth perception.

Skin Structure and Functions

Epidermis varies in thickness, notably thicker in areas subjected to wear, such as palms and soles.
Melanocytes in the germinative layer secrete melanin, affecting skin color along with factors like blood oxygen saturation and bile pigments.
Dermis, made of areolar connective tissue, consists of collagen and elastic fibers, supporting skin structure.
Key components of the dermis include blood vessels, sensory nerve endings, sweat and sebaceous glands, hair follicles, and various sensory receptors.

Functions of Human Skin

Protection: Acts as a barrier against microorganisms, chemicals, dehydration, and UV radiation due to keratinized epithelium and melanin.
Temperature Regulation: Controls heat loss/gain; sweat glands help regulate body temperature by secreting sweat when body heat increases.

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Description

Test your knowledge on Animal Form and Function, focusing specifically on Genetics for the G.C.E. Advanced Level Biology syllabus. This quiz is designed for Grade 13 students and covers essential concepts that are crucial for mastering this topic. Prepare yourself for the examination with confidence!