About this quiz
Cell, plant life and classification of living things.
This Lok Sewa practice set has 50 multiple-choice questions (Subject: General Science · For: Kharidar, Nayab Subba, Section Officer · Level: Medium). Take the quiz above first; after that, use the study list below to revise every question with its correct answer and a short explanation.
Study list: all 50 questions with answers and explanations
Who first described the cell?
- A) Robert Brown
- B) Robert Hooke ✔
- C) Leeuwenhoek
- D) Darwin
Why: Robert Hooke first described and named the 'cell' in 1665 after seeing cork under a microscope.
Who discovered the nucleus?
- A) Robert Brown ✔
- B) Schleiden
- C) Schwann
- D) Mendel
Why: Robert Brown discovered the cell nucleus in 1831 while studying orchid cells.
The cell theory was given by:
- A) Hooke and Brown
- B) Schleiden and Schwann ✔
- C) Watson and Crick
- D) Darwin and Wallace
Why: Matthias Schleiden (plants, 1838) and Theodor Schwann (animals, 1839) gave the cell theory: all living things are made of cells.
Which organelle is called the "powerhouse of the cell"?
- A) Ribosome
- B) Nucleus
- C) Mitochondria ✔
- D) Golgi body
Why: Mitochondria release energy from food through cellular respiration, making ATP, so they are the powerhouse of the cell.
Which organelle is called the "suicide bag"?
- A) Lysosome ✔
- B) Vacuole
- C) Ribosome
- D) Plastid
Why: Lysosomes contain digestive enzymes; if they burst they can digest the cell itself, so they are called suicide bags.
Proteins are made in the:
- A) Lysosome
- B) Ribosome ✔
- C) Vacuole
- D) Cell wall
Why: Ribosomes make proteins by joining amino acids according to instructions from the genes.
The plant cell wall is mainly made of:
- A) Protein
- B) Starch
- C) Cellulose ✔
- D) Chitin
Why: The plant cell wall is made mainly of cellulose, which gives the cell shape and strength.
Which is found in plant cells but not in animal cells?
- A) Mitochondria
- B) Nucleus
- C) Chloroplast ✔
- D) Ribosome
Why: Chloroplasts (and a cell wall and large vacuole) are found in plant cells, not animal cells. They carry out photosynthesis.
The longest cell in the human body is the:
- A) Muscle cell
- B) Nerve cell ✔
- C) Bone cell
- D) Red blood cell
Why: Nerve cells (neurons) are the longest cells; some run from the spine to the toes, about a metre long.
Bacteria are:
- A) Eukaryotic
- B) Prokaryotic ✔
- C) Multicellular plants
- D) Fungi
Why: Bacteria are prokaryotic: they have no true nucleus or membrane-bound organelles.
Which gas is released during photosynthesis?
- A) Carbon dioxide
- B) Nitrogen
- C) Oxygen ✔
- D) Hydrogen
Why: Photosynthesis releases oxygen, which comes from splitting water molecules.
Photosynthesis takes place in the:
- A) Mitochondria
- B) Chloroplast ✔
- C) Nucleus
- D) Root hair
Why: Photosynthesis takes place in chloroplasts, which contain the green pigment chlorophyll.
Water moves from the roots to the leaves through:
- A) Phloem
- B) Xylem ✔
- C) Stomata
- D) Cambium
Why: Xylem tissue carries water and minerals up from the roots to the leaves.
Loss of water vapour from leaves is called:
- A) Respiration
- B) Transpiration ✔
- C) Germination
- D) Pollination
Why: Transpiration is the loss of water vapour through tiny pores (stomata) in leaves. It helps pull water up and cools the plant.
Which plant hormone helps ripen fruits?
- A) Auxin
- B) Cytokinin
- C) Ethylene ✔
- D) Gibberellin
Why: Ethylene is a gaseous plant hormone that ripens fruits. It is used to ripen bananas and mangoes.
Binomial nomenclature was introduced by:
- A) Whittaker
- B) Carl Linnaeus ✔
- C) Darwin
- D) Mendel
Why: Carl Linnaeus introduced binomial nomenclature: a two-part scientific name of genus and species, such as Homo sapiens.
The five-kingdom classification was proposed by:
- A) R.H. Whittaker ✔
- B) Linnaeus
- C) Aristotle
- D) Haeckel
Why: R. H. Whittaker proposed the five kingdoms in 1969: Monera, Protista, Fungi, Plantae and Animalia.
Mushroom belongs to kingdom:
- A) Plantae
- B) Monera
- C) Fungi ✔
- D) Protista
Why: Mushrooms belong to kingdom Fungi: they have no chlorophyll and absorb food from dead matter.
Which group is called the "amphibians of the plant kingdom"?
- A) Pteridophyta
- B) Bryophyta ✔
- C) Gymnosperms
- D) Thallophyta
Why: Bryophytes (mosses, liverworts) live on land but need water for reproduction, so they are called the amphibians of the plant kingdom.
Which of these is a monocot plant?
- A) Pea
- B) Mango
- C) Rice ✔
- D) Gram
Why: Rice is a monocot: its seed has one cotyledon, and its leaves have parallel veins. Wheat, maize and bamboo are also monocots.
The basic unit of life is the:
- A) Cell ✔
- B) Tissue
- C) Organ
- D) Atom
Why: The cell is the basic structural and functional unit of life.
The cell membrane is:
- A) Selectively permeable ✔
- B) Fully permeable
- C) Impermeable
- D) Made of cellulose
Why: The cell membrane is selectively permeable: it lets some substances pass in and out but not others.
DNA is found mainly in the:
- A) Nucleus ✔
- B) Ribosome
- C) Cell wall
- D) Vacuole
Why: DNA is found mainly in the nucleus, with small amounts in mitochondria and chloroplasts.
Prokaryotic cells lack a:
- A) True nucleus ✔
- B) Cell membrane
- C) Ribosome
- D) Cytoplasm
Why: Prokaryotic cells, like bacteria, lack a true nucleus; their DNA lies free in the cytoplasm.
Chlorophyll is green and found in:
- A) Chloroplasts ✔
- B) Mitochondria
- C) Nucleus
- D) Ribosomes
Why: Chlorophyll, the green pigment that absorbs light, is found in chloroplasts.
The raw materials of photosynthesis are:
- A) Carbon dioxide and water ✔
- B) Oxygen and glucose
- C) Nitrogen and water
- D) Starch and oxygen
Why: Photosynthesis uses carbon dioxide and water, with sunlight, to make glucose and release oxygen.
The food made by plants in photosynthesis is:
- A) Glucose ✔
- B) Protein
- C) Fat
- D) Vitamin
Why: Plants make glucose in photosynthesis and store extra as starch.
Food is transported in plants through:
- A) Phloem ✔
- B) Xylem
- C) Stomata
- D) Root hairs
Why: Phloem carries food (sugars) made in the leaves to other parts of the plant.
Gas exchange in leaves takes place through:
- A) Stomata ✔
- B) Xylem
- C) Phloem
- D) Roots
Why: Stomata are tiny pores, mostly on the underside of leaves, through which carbon dioxide enters and oxygen and water vapour leave.
Which plant hormone promotes cell elongation and growth?
- A) Auxin ✔
- B) Ethylene
- C) Abscisic acid
- D) Insulin
Why: Auxin promotes cell elongation and makes shoots bend towards light.
Which hormone causes stomata to close in drought?
- A) Abscisic acid ✔
- B) Auxin
- C) Gibberellin
- D) Cytokinin
Why: Abscisic acid (ABA), the 'stress hormone', closes stomata during drought to save water.
The process of division producing two identical cells is:
- A) Mitosis ✔
- B) Meiosis
- C) Fertilisation
- D) Pollination
Why: Mitosis produces two identical daughter cells, each with the full chromosome number. It is used for growth and repair.
Meiosis produces:
- A) Gametes with half chromosomes ✔
- B) Identical body cells
- C) Roots
- D) Leaves
Why: Meiosis produces gametes (egg and sperm) with half the chromosome number, so fertilisation restores the full number.
Human body cells have how many chromosomes?
- A) 46 ✔
- B) 23
- C) 44
- D) 48
Why: Human body cells have 46 chromosomes (23 pairs); gametes have 23.
The transfer of pollen to stigma is called:
- A) Pollination ✔
- B) Fertilisation
- C) Germination
- D) Transpiration
Why: Pollination is the transfer of pollen from anther to stigma, by wind, insects, water or animals.
Plants that live for one season are called:
- A) Annuals ✔
- B) Biennials
- C) Perennials
- D) Epiphytes
Why: Annuals complete their life cycle in one season, like rice and wheat. Biennials take two years; perennials live many years.
Which is a dicot plant?
- A) Pea ✔
- B) Maize
- C) Rice
- D) Wheat
Why: Pea is a dicot: its seed has two cotyledons and its leaves have net venation.
Monocot leaves usually have:
- A) Parallel venation ✔
- B) Reticulate venation
- C) No veins
- D) Spines only
Why: Monocot leaves usually have parallel venation, as in grass, maize and banana. Dicot leaves have net (reticulate) venation.
The father of taxonomy is:
- A) Carolus Linnaeus ✔
- B) Darwin
- C) Whittaker
- D) Mendel
Why: Carolus (Carl) Linnaeus is the father of taxonomy, the science of naming and classifying organisms.
The scientific name of humans is:
- A) Homo sapiens ✔
- B) Felis catus
- C) Canis familiaris
- D) Rana tigrina
Why: Humans are Homo sapiens: genus Homo, species sapiens ('wise man').
Bacteria belong to the kingdom:
- A) Monera ✔
- B) Protista
- C) Fungi
- D) Plantae
Why: Bacteria belong to kingdom Monera, the kingdom of prokaryotes.
Amoeba belongs to the kingdom:
- A) Protista ✔
- B) Monera
- C) Fungi
- D) Animalia
Why: Amoeba is a single-celled eukaryote, so it belongs to kingdom Protista.
Animals with a backbone are called:
- A) Vertebrates ✔
- B) Invertebrates
- C) Arthropods
- D) Molluscs
Why: Animals with a backbone (vertebral column) are vertebrates: fish, amphibians, reptiles, birds and mammals.
Which is a mammal?
- A) Bat ✔
- B) Penguin
- C) Crocodile
- D) Frog
Why: The bat is a mammal: it has hair, gives birth to live young and feeds them milk. It is the only mammal that truly flies.
Which is a reptile?
- A) Snake ✔
- B) Frog
- C) Whale
- D) Shark
Why: Snakes are reptiles: cold-blooded vertebrates with scaly skin that usually lay eggs.
Insects belong to the phylum:
- A) Arthropoda ✔
- B) Mollusca
- C) Annelida
- D) Chordata
Why: Insects belong to phylum Arthropoda (jointed legs), the largest phylum of animals.
Earthworm belongs to the phylum:
- A) Annelida ✔
- B) Arthropoda
- C) Mollusca
- D) Porifera
Why: The earthworm belongs to phylum Annelida (segmented worms).
Fungi obtain food by being:
- A) Saprophytic/heterotrophic ✔
- B) Photosynthetic
- C) Chemosynthetic only
- D) Parasitic only
Why: Fungi have no chlorophyll, so they are heterotrophs; most are saprophytes that feed on dead organic matter.
Viruses are considered on the border of living and non-living because they:
- A) Reproduce only inside living cells ✔
- B) Have chlorophyll
- C) Have many cells
- D) Breathe air
Why: Viruses can reproduce only inside living cells; outside they act like non-living particles and can even form crystals.
The study of fungi is called:
- A) Mycology ✔
- B) Zoology
- C) Botany
- D) Entomology
Why: Mycology is the study of fungi.