2024 NECO BIOLOGY QUESTIONS & ANSWERS

Biology likely related questions for neco 2024

Question: Describe the structure and function of the following cell organelles: 2024 NECO BIOLOGY QUESTIONS & ANSWERS

Solution:

Nucleus:
- Structure: The nucleus is a large, membrane-bound organelle that contains the cell’s genetic material (DNA). It is surrounded by a double membrane called the nuclear envelope, which has pores to allow the exchange of materials.
- Function: The nucleus controls and regulates the activities of the cell (e.g., growth, metabolism) and carries the genes, structures that contain the hereditary information.
Mitochondria:
- Structure: Mitochondria are double-membraned organelles with an inner membrane folded into structures called cristae. They have their own DNA and ribosomes.
- Function: Mitochondria are the powerhouse of the cell, generating ATP through cellular respiration. They also play a role in cell signaling, cellular differentiation, and cell death.
Ribosomes:
- Structure: Ribosomes are small, spherical organelles made of ribosomal RNA and proteins. They can be free-floating in the cytoplasm or attached to the rough endoplasmic reticulum.
- Function: Ribosomes are the sites of protein synthesis. They translate genetic information from mRNA to synthesize proteins.

Question: Explain the process of photosynthesis, including the light-dependent and light-independent reactions.

Solution:

Photosynthesis: Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy, water, and carbon dioxide into glucose and oxygen.
Light-dependent Reactions:
- Location: Thylakoid membranes of the chloroplasts.
- Process:
  - Light energy is absorbed by chlorophyll and other pigments.
  - This energy splits water molecules (photolysis) into oxygen, protons, and electrons.
  - The electrons move through the electron transport chain, creating a proton gradient that drives the synthesis of ATP (photophosphorylation).
  - NADP+ is reduced to NADPH.
Light-independent Reactions (Calvin Cycle):
- Location: Stroma of the chloroplasts.
- Process:
  - ATP and NADPH produced in the light-dependent reactions are used to fix carbon dioxide into organic molecules.
  - Carbon dioxide combines with ribulose bisphosphate (RuBP) to form 3-phosphoglycerate (3-PGA).
  - 3-PGA is then reduced to glyceraldehyde-3-phosphate (G3P).
  - Some G3P molecules are used to form glucose, while others regenerate RuBP.

Question: Define the following genetic terms:

Solution:

Allele:
- An allele is one of two or more versions of a gene. Individuals inherit two alleles for each gene, one from each parent.
Genotype:
- The genotype refers to the genetic makeup of an organism, specifically the set of alleles it possesses for a particular gene or set of genes.
Phenotype:
- The phenotype is the observable physical or physiological traits of an organism, which result from the interaction of its genotype with the environment.

Question: Discuss the theory of natural selection as proposed by Charles Darwin.

Solution:

Theory of Natural Selection:
- Charles Darwin proposed the theory of natural selection as the mechanism of evolution. It is based on the following key points:
  1. Variation: Within a population, individuals have variations in their traits.
  2. Inheritance: Some of these variations are heritable and can be passed on to offspring.
  3. Overproduction: Most species produce more offspring than can survive to maturity.
  4. Differential Survival and Reproduction: Individuals with traits that are advantageous for survival and reproduction are more likely to survive and reproduce, passing those traits to the next generation.
  5. Accumulation of Favorable Traits: Over time, these advantageous traits become more common in the population, leading to evolutionary change.

Question: Describe the structure and function of the human heart.

Solution:

Structure: The human heart is a muscular organ located in the chest cavity. It has four chambers: two atria (upper chambers) and two ventricles (lower chambers). The right side of the heart deals with deoxygenated blood, while the left side handles oxygenated blood. The heart is equipped with valves (tricuspid, bicuspid/mitral, pulmonary, and aortic) that ensure unidirectional blood flow.
Function:
- The heart pumps blood through the circulatory system.
- Right atrium: Receives deoxygenated blood from the body through the superior and inferior vena cava.
- Right ventricle: Pumps deoxygenated blood to the lungs via the pulmonary artery.
- Left atrium: Receives oxygenated blood from the lungs through the pulmonary veins.
- Left ventricle: Pumps oxygenated blood to the body through the aorta.

Question: Explain the concept of an ecosystem and the roles of producers, consumers, and decomposers.

Solution:

Ecosystem: An ecosystem is a community of living organisms (plants, animals, and microbes) interacting with their non-living environment (air, water, and mineral soil). These interactions form a system that supports life.
Producers: Also known as autotrophs, producers are organisms that produce their own food through photosynthesis (e.g., plants) or chemosynthesis (e.g., some bacteria). They form the base of the food chain.
Consumers: Also known as heterotrophs, consumers are organisms that obtain energy by feeding on other organisms. They are classified into primary consumers (herbivores), secondary consumers (carnivores that eat herbivores), and tertiary consumers (carnivores that eat other carnivores).
Decomposers: Decomposers are organisms, such as bacteria and fungi, that break down dead or decaying organic matter, recycling nutrients back into the ecosystem.

These questions and answers should help prepare for the NECO Biology exam. If you need more questions or specific topics covered, feel free to ask!