Edexcel IGCSE Biology - 1. The Nature & Variety of Living Organisms

Define the term autotroph.

An autotroph is an organism that can produce its own food for energy.

What is the primary photosynthetic pigment in photosynthesis?

The primary photosynthetic pigment in photosynthesis is chlorophyll.

Define the term heterotroph.

A heterotroph is an organism that obtains its energy and nutrients by consuming other organisms.

What is the source of energy for plants in photosynthesis

Plants use sunlight as their primary source of energy for photosynthesis.

Define the term respiration.

Respiration is the biochemical process carried out in all living organisms

True or False? Respiration occurs only in the presence of oxygen.

False. Aerobic respiration occurs in the presence of oxygen and anaerobic respiration occurs in the absence of oxygen.

Define the term excretion.

Excretion is the process of removing waste products produced by metabolic activities from an organism.

Which term describes a plant's response to light?

The term which describes a plant's response to light is phototropism.

Define the term sensitivity.

Sensitivity refers to an organism's ability to detect and respond to stimuli in its environment.

What is movement in living organisms?

Movement is any action causing a change in position or place by an organism.

What are the main characteristics of a eukaryotic organisms?

A eukaryotic organism is an organism whose cells contain membrane-bound organelles including a nucleus.

True or False? Prokaryotic organisms contain a nucleus.

False. Prokaryotic organisms do not contain a nucleus.

True or False? Eukaryotic organisms include protoctists.

True. Eukaryotic organisms include protoctists

Define prokaryotic organism.

A prokaryotic organism is an organism whose cells lack a nucleus and other membrane-bound organelles.

What are the distinguishing features of animals?

Animals are multicellular

How do fungal cells store carbohydrates?

Fungi store carbohydrates as glycogen.

What are the distinguishing features of plants?

Plants are multicellular

Define protoctists.

Protoctists are a diverse group of microscopic single-celled eukaryotic organisms that may have features resembling animal or plant cells.

What is the feeding method of fungi known as?

The feeding method of fungi is known as saprotrophic nutrition.

True or False? Protoctists may include both photosynthetic and non-photosynthetic organisms.

True. Some protoctists perform photosynthesis

True or False? All prokaryotic organisms are single-celled.

True. Prokaryotic organisms are always single-celled.

What is a prokaryotic organism?

A prokaryotic organism is a single-celled organism that lacks a nucleus and other membrane-bound organelles.

Define the term plasmid.

A plasmid is a small circular loop of DNA found in prokaryotic cells.

True or False? Bacteria have a nucleus.

False. Bacteria lack a nucleus but contain a circular chromosome of DNA.

Describe bacterial cells.

Bacteria are microscopic

Define the term saprobiont.

A saprobiont is an organism that feeds on dead organic matter.

True or False? Bacteria contain chloroplasts.

False. Bacteria do not contain any internal membrane-bound structures

Name two examples of bacteria.

Examples of bacteria include Lactobacillus (used in yogurt production) and Pneumococcus (causing pneumonia).

Which foodstuff is produced using the bacteria Lactobacillus bulgaricus?

Lactobacillus bulgaricus is used to make yoghurt.

What is the cellular structure of a typical bacterial cell?

A typical bacterial cell consists of a cell wall

True or False? All viruses are considered living organisms.

False. Viruses are not considered living organisms because they do not carry out all life processes for themselves.

Define the term pathogen.

A pathogen is any microorganism that causes disease in another organism.

What are examples of pathogenic microorganisms?

Examples include bacteria

True or False? Influenza is caused by a bacterial pathogen.

False. Influenza is caused by a virus.

What is meant by AIDS?

AIDS is Acquired Immunodeficiency Syndrome associated with HIV-positive patients who are susceptible to opportunistic infections due to a weakened immune system.

True or False? Bacteria are smaller than viral particles.

False. Viral particles are smaller than bacteria and can only reproduce inside living cells.

Which disease is caused by Plasmodium?

Plasmodium is a protoctist that causes malaria in humans.

Why are viruses considered parasitic?

Viruses can only reproduce inside living host cells. The virus derives benefits while the relationship harms the host.

What is HIV?

HIV stands for Human Immunodeficiency Virus

How does the tobacco mosaic virus (TMV) cause damage to crops?

TMV is a plant pathogen that infects various plants