Bio IGCSE Unit 1-3

What does the G in MRS GREN stand for?

The G in MRS GREN stands for growth.

What do the two Rs in MRS GREN stand for?

The two Rs in MRS GREN stand for reproduction and respiration.

Define the term sensitivity in the context of MRS GREN.

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

What does the G in MRS GREN stand for?

The G in MRS GREN stands for growth.

What do the two Rs in MRS GREN stand for?

The two Rs in MRS GREN stand for reproduction and respiration.

Define the term sensitivity in the context of MRS GREN.

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.

How were living organisms traditionally classified into groups?

Traditional classification makes use of the structural characteristics of living organisms, e.g. body shape and internal anatomy.

True or False? The binomial naming system uses the family and genus levels of classification.

False. The binomial naming system uses genus and species.

Canis lupus is the scientific name for wolves. What does this name tell us about wolf classification?

The name Canis lupus tells us that wolves belong to the genus Canisand the species lupus.

What is the definition of a species?

A species is a group of organisms that can reproduce to produce fertile offspring.

What is a dichotomous key?

A dichotomous key is a key used to identify organisms based on a series of questions about their features. It leads the user through to the name of the organism by giving two descriptions at a time and asking them to choose.

True or False? In a dichotomous key you can start from any point in the key to identify an organism.

False. In a dichotomous key you need to follow the statements from the beginning to successfully identify an organism.

What does it mean to classify organisms on the basis of evolutionary relationship? (Extended Tier Only)

Classifying organisms on the basis of evolutionary relationship means grouping organisms on the basis of shared common ancestry; organisms with more recent common ancestors are grouped more closely than those with more distant common ancestors.

How does DNA sequencing technology contribute to organism classification? (Extended Tier Only)

DNA sequencing technology means that organisms can be classified on the basis of their DNA base sequences rather than on the basis of their observable characteristics.

True or False? Groups of organisms which share a more recent ancestor have DNA base sequences that are more similar than those that share only a distant ancestor. (Extended Tier Only)

True. The more recent the common ancestor, the more DNA base sequences the organisms will have in common.

True or False? The DNA base sequences of mammals are more closely related to other mammals than to any other vertebrate groups. (Extended Tier Only)

True. Mammals are more closely related to other mammals than to any other vertebrate group, so their DNA base sequences will be more similar to each other than to those of any other group.

What are the main features used to classify animals into the animal kingdom?

The main features used to classify animals into the animal kingdom include:

• animals are multicellular
• animal cells have a nucleus, but no cell wall or chloroplasts
• animals feed on organic molecules contained within the bodies of other organisms

True or False? All animals are multicellular organisms.

True. All animals are multicellular organisms.

True or False? Animal cells contain chloroplasts.

False. Animal cells do not contain chloroplasts.

What are the main features used to classify plants into the plant kingdom?

The main features used to classify plants into the plant kingdom include:

• plants are multicellular
• plant cells contain a nucleus, cell wall and chloroplasts
• plants make their own organic molecules by photosynthesis

Define the term vertebrate.

Vertebrates are animals that have a backbone.

What are the main groups of vertebrates?

The main groups of vertebrates are:

• mammals
• birds
• reptiles
• amphibians
• fish

What are the main features of mammals?

The main features of mammals include:

• fur, or hair
• mammary glands for the feeding of young
• regulation of internal body temperature
• diaphragm
• four-chambered heart

Define the term arthropod.

Arthropods are invertebrates with jointed legs.

What are the main groups of arthropods?

The main groups of arthropods are:

• myriapods
• insects
• arachnids
• crustaceans

What are the main features of crustaceans within the arthropod group?

Crustaceans have:

• two pairs of antennae
• a hard exoskeleton
• separate body segments
• more than four pairs of jointed legs
• gills

What are the five kingdoms in the biological classification system? (Extended Tier Only)

The five kingdoms are:

• animal
• plants
• fungi
• protoctist
• prokaryotes

What are the main features of fungi? (Extended Tier Only)

Features of fungi are:

• they are usually (but not always) multicellular
• cells contain nuclei
• cell walls are not made from cellulose
• fungi feed by saprophytic or parasitic nutrition

What are protoctists? (Extended Tier Only)

Protoctists are unicellular or multicellular organisms with a nucleus. Some may have cell walls and chloroplasts while some do not, and some can photosynthesise while others feed on organic substances.

What are the main characteristics of prokaryotes? (Extended Tier Only)

Features of prokaryotes include:

• they are unicellular
• they have cell walls that are not made of cellulose
• their cells contain cytoplasm, but no nucleus or any other membrane-bound structures

True or False? All plants reproduce using flowers and seeds. (Extended Tier Only)

False. Some plants, like ferns, reproduce by spores instead of flowers and seeds.

State two differences between monocotyledonous and dicotyledonousleaves. (Extended Tier Only)

Two differences between monocotyledonous and dicotyledonous leaves are that:

• monocotyledonous leaves have parallel leaf veins while dicotyledonous leaves have a network of veins
• monocotyledonous leaves are narrow while dicotyledon leaves tend to be broader.

What is the key difference between the flowers of monocotyledonous and dicotyledonous plants? (Extended Tier Only)

The key difference between the flowers of monocotyledonous and dicotyledonous plants is that monocotyledonous flowers have petals inmultiples of 3, whiledicotyledonous flowers have petals in multiples of 4 or 5.

Describe the basic structure of a virus. (Extended Tier Only)

A virus consists of genetic material (RNA or DNA) inside a **protein coat

What does the G in MRS GREN stand for?

The G in MRS GREN stands for growth.

What do the two Rs in MRS GREN stand for?

The two Rs in MRS GREN stand for reproduction and respiration.

Define the term sensitivity in the context of MRS GREN.

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

What does the G in MRS GREN stand for?

The G in MRS GREN stands for growth.

What do the two Rs in MRS GREN stand for?

The two Rs in MRS GREN stand for reproduction and respiration.

Define the term sensitivity in the context of MRS GREN.

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.

How were living organisms traditionally classified into groups?

Traditional classification makes use of the structural characteristics of living organisms, e.g. body shape and internal anatomy.

True or False? The binomial naming system uses the family and genus levels of classification.

False. The binomial naming system uses genus and species.

Canis lupus is the scientific name for wolves. What does this name tell us about wolf classification?

The name Canis lupus tells us that wolves belong to the genus Canisand the species lupus.

What is the definition of a species?

A species is a group of organisms that can reproduce to produce fertile offspring.

What is a dichotomous key?

A dichotomous key is a key used to identify organisms based on a series of questions about their features. It leads the user through to the name of the organism by giving two descriptions at a time and asking them to choose.

True or False? In a dichotomous key you can start from any point in the key to identify an organism.

False. In a dichotomous key you need to follow the statements from the beginning to successfully identify an organism.

What does it mean to classify organisms on the basis of evolutionary relationship? (Extended Tier Only)

Classifying organisms on the basis of evolutionary relationship means grouping organisms on the basis of shared common ancestry; organisms with more recent common ancestors are grouped more closely than those with more distant common ancestors.

How does DNA sequencing technology contribute to organism classification? (Extended Tier Only)

DNA sequencing technology means that organisms can be classified on the basis of their DNA base sequences rather than on the basis of their observable characteristics.

True or False? Groups of organisms which share a more recent ancestor have DNA base sequences that are more similar than those that share only a distant ancestor. (Extended Tier Only)

True. The more recent the common ancestor, the more DNA base sequences the organisms will have in common.

True or False? The DNA base sequences of mammals are more closely related to other mammals than to any other vertebrate groups. (Extended Tier Only)

True. Mammals are more closely related to other mammals than to any other vertebrate group, so their DNA base sequences will be more similar to each other than to those of any other group.

What are the main features used to classify animals into the animal kingdom?

The main features used to classify animals into the animal kingdom include:

• animals are multicellular
• animal cells have a nucleus, but no cell wall or chloroplasts
• animals feed on organic molecules contained within the bodies of other organisms

True or False? All animals are multicellular organisms.

True. All animals are multicellular organisms.

True or False? Animal cells contain chloroplasts.

False. Animal cells do not contain chloroplasts.

What are the main features used to classify plants into the plant kingdom?

The main features used to classify plants into the plant kingdom include:

• plants are multicellular
• plant cells contain a nucleus, cell wall and chloroplasts
• plants make their own organic molecules by photosynthesis

Define the term vertebrate.

Vertebrates are animals that have a backbone.

What are the main groups of vertebrates?

The main groups of vertebrates are:

• mammals
• birds
• reptiles
• amphibians
• fish

What are the main features of mammals?

The main features of mammals include:

• fur, or hair
• mammary glands for the feeding of young
• regulation of internal body temperature
• diaphragm
• four-chambered heart

Define the term arthropod.

Arthropods are invertebrates with jointed legs.

What are the main groups of arthropods?

The main groups of arthropods are:

• myriapods
• insects
• arachnids
• crustaceans

What are the main features of crustaceans within the arthropod group?

Crustaceans have:

• two pairs of antennae
• a hard exoskeleton
• separate body segments
• more than four pairs of jointed legs
• gills

What are the five kingdoms in the biological classification system? (Extended Tier Only)

The five kingdoms are:

• animal
• plants
• fungi
• protoctist
• prokaryotes

What are the main features of fungi? (Extended Tier Only)

Features of fungi are:

• they are usually (but not always) multicellular
• cells contain nuclei
• cell walls are not made from cellulose
• fungi feed by saprophytic or parasitic nutrition

What are protoctists? (Extended Tier Only)

Protoctists are unicellular or multicellular organisms with a nucleus. Some may have cell walls and chloroplasts while some do not, and some can photosynthesise while others feed on organic substances.

What are the main characteristics of prokaryotes? (Extended Tier Only)

Features of prokaryotes include:

• they are unicellular
• they have cell walls that are not made of cellulose
• their cells contain cytoplasm, but no nucleus or any other membrane-bound structures

True or False? All plants reproduce using flowers and seeds. (Extended Tier Only)

False. Some plants, like ferns, reproduce by spores instead of flowers and seeds.

State two differences between monocotyledonous and dicotyledonousleaves. (Extended Tier Only)

Two differences between monocotyledonous and dicotyledonous leaves are that:

• monocotyledonous leaves have parallel leaf veins while dicotyledonous leaves have a network of veins
• monocotyledonous leaves are narrow while dicotyledon leaves tend to be broader.

What is the key difference between the flowers of monocotyledonous and dicotyledonous plants? (Extended Tier Only)

The key difference between the flowers of monocotyledonous and dicotyledonous plants is that monocotyledonous flowers have petals inmultiples of 3, whiledicotyledonous flowers have petals in multiples of 4 or 5.

Describe the basic structure of a virus. (Extended Tier Only)

A virus consists of genetic material (RNA or DNA) inside a **protein coat

What separates cells from their surrounding environment?

The cell membrane separatescells from their surrounding environment.

Name the largest organelle present within animal cells.

The largest organelle within animal cells is the nucleus.

Name the structures present in plant cells that are not present in animal cells.

Plant cells have the following structures that are not present in animal cells:

• cell wall
• chloroplasts
• permanent vacuole

True or False? Ribosomes are present in both plant and animal cells.

True. Ribosomes are present in plant and animal cells. They are the site of protein synthesis.

Name three organelles found within animal cells.

Organelles present within animal cells are:

• nucleus
• mitochondria
• ribosomes
  Note that structures such as the cell membrane and cytoplasm are not organelles, so are not acceptable answers here.

What is the smallest organelle present in both plant and animal cells?

Ribosomes are the smallest organelle; they are present in both plant and animal cells.

True or False? The gel-like fluid present inside both plant and animal cells is the chloroplast.

False. The gel-like fluid present in plant and animal cells is the cytoplasm. Chloroplasts are organelles found in plant cells.

True or False? The role of the nucleus is to release energy for the cell.

False. The role of the nucleus is to store genetic information in the form of DNA. Energy is released by the mitochondria.

What is the function of the cell membrane?

The cell membrane controls thepassage of substances in and out of the cell.

True or False? Muscle cells are likely to contain more mitochondria than skin cells.

True. Muscle cells are likely to contain more mitochondria than skin cells. This is because they are more metabolically active, so will need more energy from respiration, the process that occurs inside mitochondria.

True or False? Mitochondria are the site of aerobic respiration.

True. Mitochondria are responsible for releasing energy through the process of aerobic respiration.

True or False? Ribosomes are the site of protein synthesis.

True. Ribosomes are responsible for protein synthesis, the process by which proteins are made.

What is the role of cell cytoplasm?

Cytoplasm is the site of chemical reactions inside cells.

What is the function of chloroplasts within plant cells?

Chloroplasts absorb light energy during the process of photosynthesis.

True or False? Plant cell walls are responsible for controlling the passage of substances in and out of cells.

False. Plant cell walls provide strength and additional structural support for plant cells. It is the membrane that regulates the passage of substances.

What is the function of the permanent vacuole in plant cells?

The permanent vacuole stores cell sap and provides structural support for plant cells.

True or False? Animal cells have mitochondria, ribosomes and a cell wall.

False. Animal cells contain mitochondria and ribosomes but do not have cell walls. Cell walls are a feature of plant cells.

Give three differences between plant and animal cells.

Three differences between plant and animal cells are:

• Plant cells contain chloroplasts while animal cells do not
• Plant cells have a cell wall while animal cells do not
• Plant cells have a permanent vacuole while animal cells do not

Describe the permanent vacuole.

The permanent vacuole in plant cells is a membrane-bound structure that stores cell sap and helps maintain cell shape.

True or False? Mitochondriaare the site of photosynthesis in plant cells.

False. Mitochondria are the site of (aerobic) respiration. Chloroplasts are the site of photosynthesis.

True or False? Cell membranes provide structural support to plant and animal cells.

False. The cell membrane does not have a rigid structure so does not provide any structural support. Its role is to control what enters and leaves the cell.

Which cellular structure contains the genetic material in both plant and animal cells?

The nucleus contains the genetic material, DNA, in both plant and animal cells.

List the structural features that are found in both plant and animal cells.

Structural features present in both plant and animal cells are:

• Cell membrane
• Cytoplasm
• Nucleus
• Mitochondria
• Ribosomes

True or False? Plant cells do not contain mitochondria.

False. Plant cells do contain mitochondria. Mitochondria are the site of aerobic respiration, a process that is essential for both plant and animal cells.

How are new cells produced?

New cells are produced by division of existing cells, e.g. by mitosis or meiosis.

Define the term specialised cell.

Specialised cells are cells that have developed specific characteristics that allow them to perform particular functions.

How are red blood cells specialised to carry out their function?

Red blood cells have a large surface area to increase diffusion of oxygen and contain haemoglobin which binds to and transports oxygen. They have no nucleus to allow more space for haemoglobin.

Give an example of a specialised plant cell.

Examples of specialised plant cells include:

• Root hair cell
• Palisade mesophyll cell
• Xylem vessel