Science Term 1 Revision

Unit 1

100

What do you call the type of carbohydrate where most plants, including rice, potatoes and wheat, store their energy?

Starch

200

You can use iodine to test foods for starch. If starch is present, the orange-yellow iodine solution becomes _________.

blue-black

300

Is it necessary to remove chlorophyll from the leaf using ethanol? Yes or no?

Yes.

400

Give two (2) examples of mineral salts that are needed by plants.

Magnesium and Nitrate

500

Explain in 1 sentence why a plant that does not have enough nitrate and magnesium will not grow well.

A plant deficient in nitrate and magnesium will not grow well because nitrate is essential for protein synthesis and magnesium is a critical component of chlorophyll, both of which are crucial for fundamental metabolic processes and overall plant growth.

Unit 2

100

What do you call the part of the flower that attracts insects?

petal

200

What are the male and female parts of the flower?

Male Parts:

1. Stamen: The stamen is the male reproductive organ of a flower, and it consists of two main parts:
   • Anther: The anther is the pollen-producing part located at the top of the stamen.
   • Filament: The filament is the stalk that supports the anther.

Female Parts:

1. Pistil (or Carpel): The pistil is the female reproductive organ of a flower, and it typically consists of three parts:
   • Stigma: The stigma is the receptive surface at the top of the pistil where pollen lands.
   • Style: The style is the slender tube that connects the stigma to the ovary.
   • Ovary: The ovary is the enlarged base of the pistil that contains ovules, which develop into seeds after fertilization.

300

What is meant by seed dispersal?

Seed dispersal refers to the movement or transportation of seeds away from the parent plant to new locations, facilitating their germination and the establishment of new plants. This process is essential for the survival, genetic diversity, and colonization of plant species in different environments. Various mechanisms, such as wind, animals, water, and other factors, contribute to the dispersal of seeds.

400

Describe two ways of seed dispersal.

Seed dispersal is a crucial ecological process that ensures the spread of plant species. There are several ways seeds can be dispersed, and these methods can be categorized into various mechanisms. Here are some common ways of seed dispersal:

1. Wind Dispersal (Anemochory)

2. Animal Dispersal (Zoochory)

3. Explosive Mechanisms (Ballistochory)

4. Water Dispersal (Hydrochory)

5. Ant Dispersal (Myrmecochory)

6. Gravity Dispersal (Gravitropism)

500

What is the process of fertilisation for plants after the flowers have successfully pollinated? Explain your answer in 1 sentence only.

After successful pollination, the pollen grain travels down the style to the ovary, where it fuses with the ovule, leading to fertilization and the formation of a seed within the developing fruit.

Unit 3

100

Give 3 examples of habitats of animals.

• Rainforest Habitat
• Desert Habitat
• Ocean Habitat (Coral Reef)
• Tundra
• Desert
• Freshwater

200

Name one producer in a food web.

Grass or herbivours in general.

300

Give 1 structural and 1 behavioural adaptations of penguins.

1. Structural Adaptation:

   • Example: Dense, waterproof feathers
     • Description: Penguins have a layer of closely packed, short feathers that are waterproof, providing insulation and reducing heat loss while swimming in cold waters.

2. Behavioral Adaptation:

   • Example: Huddling behavior
     • Description: Penguins often engage in huddling behavior, where they gather in large groups to share body heat and protect themselves from the harsh cold of their Antarctic or sub-Antarctic environments.

400

Give 1 structural and 1 behavioural adaptations of makahiya plant.

Structural Adaptation:

• Example: Mimosa pudica's Leaf Folding
  • Description: The Makahiya plant, also known as Mimosa pudica, has a structural adaptation where its compound leaves fold inward and droop when touched or exposed to heat, a defense mechanism against herbivores.

Behavioral Adaptation:

• Example: Rapid Leaf Movement
  • Description: When the Makahiya plant is touched or disturbed, it exhibits rapid leaf movement, where the leaflets fold up quickly as a defensive response to potential threats, a behavioral adaptation to deter herbivores.

500

What does the arrow mean in a food web? Express your answer briefly in 1 sentence.

In a food web, the arrow represents the direction of energy flow, indicating the transfer of energy from one organism (or trophic level) to another as one organism is consumed by another.

Unit 4

100

What is meant by the word decomposer?

A decomposer is an organism, typically a microorganism like bacteria or fungi, that breaks down and feeds on dead organic matter, breaking it into simpler substances. Decomposers play a crucial role in the decomposition process, recycling nutrients back into the ecosystem and facilitating the breakdown of dead plants, animals, and other organic material. This process is essential for nutrient cycling and maintaining the balance of ecosystems.

200

Give two examples of invertebrates as a decomposer.

Earth worm and snail

300

Give an example of a decomposer that is also a producer.

Moss

400

Explain the process through which the fungus decomposes the leaf in 1 sentence only.

The fungus decomposes the leaf by secreting enzymes that break down complex organic compounds into simpler molecules, which the fungus then absorbs as nutrients.

500

Explain the significance of organisms that break down waste materials in an ecosystem in 1 sentence only.

Organisms that break down waste materials play a crucial role in recycling nutrients, maintaining ecosystem health, and ensuring the efficient decomposition of organic matter, contributing to the balance and sustainability of the ecosystem.

Units 5-6

100

What are classification keys for?

Classification keys are tools used to identify and categorize living organisms based on their characteristics, facilitating the systematic organization of biodiversity.

200

What is selective breeding?

Selective breeding, also known as artificial selection, is a process in which humans intentionally choose and encourage the reproduction of individuals with desired traits or characteristics to produce offspring with those specific traits.

300

What is meant by Natural Selection?

Natural selection is the process by which organisms with traits that are better suited to their environment tend to survive and reproduce more successfully than those with less advantageous traits.

400

Give one similarity of selective breeding and natural selection.

One similarity between selective breeding and natural selection is that both processes involve the differential reproduction of individuals based on their heritable traits, leading to changes in the characteristics of a population over time.

500

Who is Charles Darwin in 1 sentence.

Charles Darwin was a British naturalist and biologist who formulated the theory of evolution by natural selection, profoundly influencing our understanding of the origin and diversity of species.