Characteristics & Classification of Living Organisms

What is movement in living organisms?

an action by an organism or part of an organism causing a change of position or place.

Define respiration in living organisms?

chemical reactions that break down nutrient molecules in living cells to release energy for metabolism.

What is sensitivity in living organisms?

the ability to detect or sense stimuli in the internal or external environment and to respond appropriately.

Explain growth in living organisms?

a permanent increase in size and dry mass by an increase in cell number or cell size or both.

Define reproduction in living organisms?

it refers to the processes that produce more of the same kind of organism.

What is excretion in living organisms?

it involves the removal from organisms of toxic materials, waste products of metabolism, and substances in excess of requirements.

Describe nutrition in living organisms?

it is the process of taking in materials for energy, growth, and development.

What mnemonic can be used to remember the characteristics of living organisms?

MRS. GREN - Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

How can DNA sequences be used to determine species relationships?

They can indicate how closely related different species are.

Name the five kingdoms in the classification system and provide an example of each.

Animals (e.g., mammals), Plants (e.g., trees), Fungi (e.g., mushrooms), Protoctists (e.g., Amoeba), Prokaryotes (e.g., bacteria).

What are the main features of animals within the animal kingdom?

Animals are multicellular, have cells containing a nucleus but no cell walls or chloroplasts, and they feed on organic substances made by other living things.

Differentiate between vertebrates and invertebrates?

Vertebrates have a backbone, while invertebrates do not.

Describe the main features of Protoctists?

They are mostly unicellular but some are multicellular. They all have a nucleus, and some may have cell walls and chloroplasts.

What are the main features of Prokaryotes?

They are often unicellular. They have cell walls (not made of cellulose) and cytoplasm, but no nucleus or mitochondria.

Why aren't viruses considered part of any classification system for living things?

They do not carry out the seven life processes for themselves; instead, they take over a host cell’s metabolic pathways to replicate.

Define homeostasis?

It is the ability of an organism or cell to regulate its internal environment to maintain a stable condition.

What are the main characteristics of plants within the plant kingdom?

They are multicellular, have cells containing a nucleus, cell walls, and chloroplasts. They also perform photosynthesis.

Differentiate between multicellular and unicellular organisms?

Multicellular organisms are composed of many cells, while unicellular organisms are composed of a single cell.

Explain the significance of mitochondria in living cells?

They are organelles responsible for producing energy through cellular respiration.

Describe the role of chloroplasts in plant cells?

They are organelles where photosynthesis occurs, allowing plants to convert light energy into chemical energy.

What is the primary function of a cell wall?

It provides structural support and protection to the cell.

Differentiate between eukaryotic and prokaryotic cells?

Eukaryotic cells have a nucleus and other membrane-bound organelles, while prokaryotic cells lack a nucleus and other membrane-bound organelles.

Explain the process of photosynthesis?

It is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

What is the primary function of the nucleus in a cell?

It contains genetic material (DNA) and controls the activities of the cell.

Describe the structure of a virus?

It consists of genetic material (either DNA or RNA) enclosed in a protein coat

What are the main characteristics of fungi within the fungi kingdom?

They are multicellular organisms that have cell walls but lack chlorophyll.

Explain the role of ribosomes in protein synthesis?

They are cellular structures where protein synthesis occurs.

Describe the main features of animals classified as vertebrates?

They have a backbone (vertebral column) and a well-developed nervous system.

What is the role of lysosomes in a cell?

They are membrane-bound organelles that contain digestive enzymes, which break down waste materials and cell waste.

What are eukaryotic organisms, and how do they differ from prokaryotic organisms?

They have cells with a distinct nucleus and membrane-bound organelles, while prokaryotic organisms lack a distinct nucleus and membrane-bound organelles.

Define homeostasis and its significance in living organisms.

It is the ability of an organism to regulate its internal environment to maintain a stable condition, ensuring optimal conditions for cellular functions.

What are the main characteristics of animals within the animal kingdom?

They are multicellular, lack cell walls and chloroplasts, feed on organic substances, and often store carbohydrates as glycogen.

Describe the primary function of the cell wall in plants.

It provides structural support and protection to plant cells.

Explain the role of mitochondria in cells?

They are organelles responsible for producing energy through cellular respiration.

What are some examples of organisms classified as fungi?

Moulds, mushrooms, and yeasts.

Describe the main features of plants within the plant kingdom?

They are multicellular, have cell walls made of cellulose, contain chloroplasts, and store carbohydrates as starch or sucrose.

What is the primary function of chloroplasts in plant cells?

They are responsible for photosynthesis, converting light energy into chemical energy.

How do multicellular fungi differ from single-celled fungi?

They are mainly composed of thread-like structures called hyphae, while single-celled fungi exist as individual cells, such as yeast.

Describe the primary function of lysosomes in cells?

They contain digestive enzymes that break down waste materials and cellular debris in cells.

What are some examples of organisms classified as protoctists?

amoeba, Paramecium, Plasmodium, and Chlorella.

What are the characteristics of a typical animal cell?

It lacks cell walls and chloroplasts, and may store carbohydrates as glycogen.

What are the characteristics of a typical plant cell?

It is eukaryotic, has a cell wall made of cellulose, contains chloroplasts, and may store carbohydrates as starch or sucrose.

How do eukaryotic organisms differ from prokaryotic organisms?

They have cells with a distinct nucleus and membrane-bound organelles, while prokaryotic organisms lack a distinct nucleus and membrane-bound organelles.

What are the main features of fungi?

They are usually multicellular but some are single-celled, have cell walls made of chitin, and feed by secreting digestive enzymes onto food.

What are some examples of organisms classified as plants?

trees, flowers, grasses, and shrubs.

What are some characteristics of single-celled protoctists?

They are mainly microscopic and may exhibit features more like animal or plant cells.

What is the main function of the mycelium in fungi?

the absorption of nutrients from the environment.

What are some examples of organisms classified as animals?

mammals, birds, reptiles, amphibians, and fish.

What is the main function of the nucleus in a cell?

It contains genetic material (DNA) and controls the activities of the cell.

How do prokaryotic organisms differ from eukaryotic organisms?

They lack a distinct nucleus and membrane-bound organelles, while eukaryotic organisms have cells with a distinct nucleus and membrane-bound organelles.

What are some examples of organisms classified as prokaryotes?

bacteria and blue-green algae.

What are some characteristics of single-celled fungi?

They exist as individual cells and may reproduce by budding, e.g. yeast.

How do multicellular protoctists differ from single-celled protoctists?

They may aggregate into larger forms, such as colonies or chains of cells forming filaments.

Describe the process of photosynthesis?

It is the process by which green plants and some other organisms use sunlight to synthesize foods, such as glucose, with the help of chlorophyll.

What are the main characteristics of protoctists?

They are mainly microscopic and single-celled but may exhibit features more like animal or plant cells.

What is the primary function of respiration in living organisms?

It involves chemical reactions that break down nutrient molecules to release energy for cellular functions.