Theory

CH17 - SELECTION AND EVOLUTION

Several different processes can affect allele frequencies in populations.(a) Outline the processes that may affect allele frequencies in wildlife popu...

2024 Winter

3

Theory

CH17 - SELECTION AND EVOLUTION

Variation exists in populations of a species and this may provide the opportunity for evolution to occur.(a) Phenotypic variation exists in many forms...

2024 Summer

3

Theory

CH17 - SELECTION AND EVOLUTION

Genes have a role in determining the overall phenotype of an organism.(a) Using haemophilia as an example, explain the relationship between a gene, a ...

2024 Summer

1

Theory

CH17 - SELECTION AND EVOLUTION

(a) Variation in a particular characteristic can be described as either discontinuous or continuous. Table 5.1 contains a list of statements that app...

2024 Winter

3

Theory

CH17 - SELECTION AND EVOLUTION

Complete the following paragraphs using the most appropriate word or words.The theory of evolution describes a process that can lead to the formation ...

2024 Spring

3

Theory

CH17 - SELECTION AND EVOLUTION

(a) Young spadefoot toads are called tadpoles and live in water in ponds.S. multiplicata tadpoles show three different phenotypes due to genetic varia...

2024 Winter

3

Theory

CH17 - SELECTION AND EVOLUTION

It has been hypothesised that the mutation rate of an animal species may affect how fast animals of that species age and how long they live (lifespan)...

2024 Summer

3

Theory

CH17 - SELECTION AND EVOLUTION

The harlequin ladybird, Harmonia axyridis, is an insect that shows discontinuous variation in colour pattern and continuous variation in body size.(a)...

2024 Summer

3

Theory

CH17 - SELECTION AND EVOLUTION

(a) Young spadefoot toads are called tadpoles and live in water in ponds.S. multiplicata tadpoles show three different phenotypes due to genetic varia...

2024 Winter

2

Theory

CH17 - SELECTION AND EVOLUTION

Oryza is a genus of grass plants that includes the rice, Oryza sativa, a food crop.(a) Farmers flood fields of rice because this encourages faster gro...

2023 Summer

3

Theory

CH9 - GAS EXCHANGE AND SMOKING

(a) Fig. 1.1 is an image of a transverse section through the trachea of the gas exchange system.Write the names of structures X and Y on Fig. 1.1 in t...

2021 Spring

3

Theory

CH2 - BIOLOGICAL MOLECULES

Starch molecules are the main storage molecules in many types of cereal grain, such as the grainof the barley plant.(a) When the seed inside a barley ...

2021 Spring

3

Theory

CH11 - IMMUNITY

T-helper lymphocytes and Leydig cells are two types of mammalian cells. The main role of T-helper lymphocytes and Leydig cells is to synthesise and se...

2021 Spring

3

Theory

CH8 - TRANSPORT IN MAMMALS

(a) Using a light microscope at a magnification of ×400, it is possible to identify different types of blood cell in prepared slides of mammalian blo...

2021 Spring

3

Theory

CH5 - THE MITOTIC CELL CYCLE

Each meristem cell in a leaf bud is able to grow and divide by mitosis to produce two daughter cells that are genetically identical to each other and ...

2021 Spring

3

Theory

CH10 - INFECTIOUS DISEASE

In March 2019, a tropical cyclone in the south-west Indian Ocean caused widespread flooding in a number of countries.The flooding and the damage cause...

2021 Spring

3

Theory

CH17 - SELECTION AND EVOLUTION

(a) The European eel, Anguilla anguilla, is a fish. The sizes of eel populations tend to remain relatively stable despite eels producing large numbers...

2021 Spring

3

Theory

CH18 - BIODIVERSITY, CLASSIFICATION AND CONSERVATION

(a) The grey wolf, *Canis lupus*, is a large predator. During the 20th century, the grey wolf in south-west Europe was hunted almost to extinction.Fig...

2021 Spring

3

Theory

CH19 - GENETIC TECHNOLOGY

Vitamin A deficiency is a widespread public health problem.One source of vitamin A is carotene in the diet. Carotene can be converted to vitamin A in ...

2021 Spring

2

Theory

CH13 - PHOTOSYNTHESIS

Red algae are multicellular photosynthetic prototists that contain phycoerythrin. Phycoerythrin is a photosynthetic pigment.(a) Fig. 4.1 shows:• the...

2021 Spring

3