Cell Structure & Size Of Specimens

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Notes de leçon

Animal Cell Structure

Contains a nucleus with a distinct membrane.
No cellulose cell wall.
No chloroplasts (cannot photosynthesise).
Carbohydrates stored as glycogen.

A typical animal cell

Plant Cell Structure

Contains a nucleus with a distinct membrane.
Cell wall made of cellulose.
Contains chloroplasts for photosynthesis.
Carbohydrates stored as starch or sucrose.
Has a permanent vacuole containing cell sap.

A typical plant cell

Common Cell Structures & Functions

Nucleus: contains DNA, controls cell activities.
Cytoplasm: gel-like, site of chemical reactions.
Cell membrane: controls entry/exit of substances.
Ribosomes: site of protein synthesis.
Mitochondria: site of aerobic respiration.

Bacterial Cell Structure

Single-celled, microscopic prokaryotes.
Cell wall made of peptidoglycan (not cellulose).
No nucleus; circular chromosome of DNA floats in cytoplasm.
May contain plasmids (small rings of extra DNA).
No mitochondria or chloroplasts.
Some have flagella for movement.

A typical bacterial cell

Specialised Cells

Cells differentiate to perform specific functions.
Examples in animals: ciliated cell, nerve cell, red blood cell, sperm cell.
Examples in plants: root hair cell, xylem vessel, palisade mesophyll cell.

Root hair cell

Levels of Organisation

Cells → Tissues (group of similar cells) → Organs → Organ systems.
Tissues are made of one type of cell.

Levels of organisation

Magnification Formula

Magnification = Image size ÷ Actual size.
Use the equation triangle: cover the value you need.
Magnification has no units (e.g., ×3000).
Always convert units to the same before calculating.

Converting Between Units (Extended)

1 mm = 1000 μm; 1 cm = 10,000 μm.
Convert all measurements to the same unit before using the magnification formula.
Example: leaf thickness 2000 μm = 2 mm; drawing 50 mm → magnification = 50/2 = ×25.

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1.Which of the following structures is found in plant cells but not in animal cells?
Easy
- ACell membrane
- BMitochondrion
- CChloroplast
- DNucleus
2.Which of the following is the function of the cell membrane?
Easy
- ASite of protein synthesis
- BControls substances entering and leaving the cell
- CContains genetic material
- DSite of aerobic respiration
3.What is the function of ribosomes?
Easy
- AProtein synthesis
- BPhotosynthesis
- CStorage of cell sap
- DControl of cell activities
4.Which of the following is found in bacteria but not in animal or plant cells?
Easy
- ACell wall
- BPlasmid
- CRibosome
- DCytoplasm
5.The image of a cell is 20 mm long. The actual cell is 0.02 mm long. What is the magnification?
Medium
- A×1000
- B×100
- C×0.001
- D×10
6.A student measures the image of a mitochondrion as 6 mm. The magnification is ×30 000. What is the actual size of the mitochondrion?
Medium
- A0.0002 mm
- B0.2 mm
- C0.02 mm
- D0.002 mm
7.Which of the following is the correct order of levels of organisation in a multicellular organism, from simplest to most complex?
Easy
- ACell → tissue → organ → organ system → organism
- BTissue → cell → organ → organ system → organism
- CCell → organ → tissue → organ system → organism
- DOrgan → tissue → cell → organ system → organism
8.Which of the following is a specialised cell in animals?
Easy
- ARoot hair cell
- BPalisade mesophyll cell
- CSperm cell
- DXylem cell

Plus de questions

9.A bacterium has a flagellum. What is the function of the flagellum?
Easy
- ATo attach to surfaces
- BTo aid movement
- CTo protect the cell
- DTo absorb nutrients
10.Which of the following statements about bacteria is correct?
Medium
- ABacteria have a nucleus containing DNA.
- BBacteria have mitochondria for respiration.
- CBacteria have a cell wall made of cellulose.
- DBacteria have a circular chromosome of DNA in the cytoplasm.
11.The actual thickness of a leaf is 2 mm. The thickness of the leaf in a diagram is 50 mm. What is the magnification of the diagram?
Medium
- A×25
- B×0.04
- C×100
- D×50
12.A student observes a cell under a light microscope and sees a large, central vacuole and chloroplasts. Which type of cell is most likely being observed?
Easy
- AAnimal cell
- BPlant cell
- CBacterial cell
- DFungal cell
13.A student measures the image of a chloroplast as 15 mm. The magnification is ×5000. What is the actual size of the chloroplast in micrometres?
Medium
- A3 μm
- B30 μm
- C0.3 μm
- D300 μm
14.In an experiment, beetroot cores were placed in water baths at different temperatures. The mean percentage transmission of light decreased as temperature increased. Which statement best explains this result?
Medium
- AHigher temperatures damage cell membranes, releasing pigment into the water.
- BHigher temperatures cause the beetroot to produce more pigment.
- CHigher temperatures increase the rate of photosynthesis in beetroot.
- DHigher temperatures cause the beetroot cells to shrink.
15.The diagram shows a plant cell. Which labelled structure is the site of aerobic respiration?
Easy
- AMitochondrion
- BChloroplast
- CNucleus
- DVacuole
16.A student used a cork borer to cut beetroot cores and placed them in water baths at different temperatures. After 30 minutes, the percentage transmission of light was measured using a colorimeter. What is the independent variable in this investigation?
Medium
- ATemperature
- BPercentage transmission of light
- CLength of beetroot core
- DTime in water bath
17.A student observes a cell under a light microscope and sees a large central vacuole and chloroplasts. Which type of cell is being observed?
Easy
- APlant cell
- BAnimal cell
- CBacterial cell
- DFungal cell
18.A student observed a cell under a light microscope and saw a nucleus, cytoplasm, cell membrane, and many mitochondria. Which type of cell is most likely being observed?
Easy
- AAnimal cell
- BPlant cell
- CBacterial cell
- DFungal cell
19.A student investigates the effect of temperature on cell membrane permeability using beetroot. Which of the following is the dependent variable?
Medium
- APercentage transmission of light
- BTemperature of water bath
- CLength of beetroot core
- DTime in water bath
20.Which of the following is found in plant cells but not in animal cells?
Easy
- ACell wall made of cellulose
- BCell membrane
- CMitochondria
- DRibosomes
21.Which of the following structures is found in animal cells?
Easy
- ACell membrane
- BCell wall
- CChloroplast
- DPermanent vacuole
22.What is the main energy-releasing organelle in a cell?
Easy
- AMitochondrion
- BNucleus
- CRibosome
- DChloroplast
23.A student observes a cell under a light microscope and sees a nucleus, cytoplasm, cell membrane, and many mitochondria. Which type of cell is most likely being observed?
Easy
- AAnimal cell
- BPlant cell
- CBacterial cell
- DFungal cell
24.Which of the following is a function of the nucleus?
Easy
- AContains DNA and controls cell activities
- BSite of protein synthesis
- CSite of aerobic respiration
- DControls entry and exit of substances
25.Which of the following is found in both plant and animal cells?
Easy
- ACell membrane
- BCell wall
- CChloroplast
- DPermanent vacuole
26.What is the function of the permanent vacuole in a plant cell?
Easy
- AStorage of cell sap and support
- BSite of photosynthesis
- CControl of cell activities
- DProtein synthesis
27.Which of the following is true about bacterial cells?
Easy
- AThey have a circular chromosome of DNA.
- BThey have a nucleus.
- CThey contain mitochondria.
- DThey have chloroplasts.
28.A student observes a cell under an electron microscope and sees rough endoplasmic reticulum. What is the function of the ribosomes attached to it?
Easy
- AProtein synthesis
- BLipid synthesis
- CEnergy release
- DPhotosynthesis
29.A plant cell is 50 μm long. What is its length in mm?
Easy
- A0.05 mm
- B0.5 mm
- C5 mm
- D0.005 mm
30.In an experiment, beetroot cores were placed in water baths at different temperatures. The percentage transmission of light through the water was measured after 30 minutes: | Temperature / °C | Mean transmission / % | |---|---| | 0 | 99.5 | | 20 | 96.3 | | 40 | 79.6 | | 60 | 30.5 | | 80 | 0.8 | | 100 | 0.0 | What conclusion can be drawn from these results?
Medium
- AHigher temperatures increase the permeability of the cell membrane.
- BHigher temperatures decrease the permeability of the cell membrane.
- CTemperature has no effect on cell membrane permeability.
- DThe beetroot pigment is destroyed at high temperatures.
31.A student uses a light microscope to view a plant cell. They see a large central vacuole and chloroplasts. Which of the following statements about this cell is correct?
Medium
- AIt is a palisade mesophyll cell.
- BIt is a root hair cell.
- CIt is an animal cell.
- DIt is a bacterial cell.
32.The image of a bacterium is 40 mm long. The magnification is ×8000. What is the actual length of the bacterium in micrometres (μm)?
Medium
- A5 μm
- B50 μm
- C0.5 μm
- D500 μm
33.Which of the following structures is found in both plant and bacterial cells but not in animal cells?
Easy
- ACell wall
- BNucleus
- CMitochondrion
- DChloroplast
34.A student measures the length of a line AB on a photomicrograph of a bronchus as 55 mm. The actual diameter of the bronchus is 1.5 mm. What is the magnification of the photomicrograph?
Medium
- A×36.7
- B×0.027
- C×36
- D×37
35.Which of the following is found in bacteria but not in animal cells?
Easy
- ACircular DNA
- BMitochondria
- CNucleus
- DCell membrane
36.Which of the following are found in both plant and animal cells? (Select all that apply)
Medium
- ANucleus
- BCell wall
- CMitochondria
- DChloroplasts
- ERibosomes
37.Bacterial cells have a nucleus containing their DNA.
Easy
True or false?
38.Match each cell structure with its function.
Easy
- Nucleus
- Ribosome
- Chloroplast
- Protein synthesis
- Contains genetic material
- Photosynthesis
39.Arrange the following levels of biological organisation from simplest to most complex.
Easy
- tissue
- organ system
- cell
- organ
- organism
40.A student views a cell under a light microscope and observes a large central vacuole and many chloroplasts. Which type of cell is most likely being observed?
Easy
- AA liver cell
- BA palisade mesophyll cell
- CA red blood cell
- DA nerve cell
41.Which of the following are found in plant cells but not in animal cells? (Select all that apply)
Medium
- ACell wall
- BChloroplast
- CMitochondrion
- DPermanent vacuole
- ERibosome
42.A student observes a cell under a light microscope and sees a cell wall, a large central vacuole, and many chloroplasts. Which of the following statements about this cell is correct?
Medium
- AIt is an animal cell because it has a cell wall.
- BIt is a bacterial cell because it has a cell wall.
- CIt is a plant cell because it has chloroplasts and a large central vacuole.
- DIt is a fungal cell because it has a vacuole.
43.Bacterial cells contain mitochondria.
Easy
True or false?
44.A student measures the length of a bacterial cell in a diagram as 40 mm. The magnification is ×8000. What is the actual length of the bacterium in micrometres (μm)?
Medium
45.Complete the sentence about the levels of organisation in a multicellular organism.
Easy
The correct order from simplest to most complex is: cells → ____ → organs → ____.
46.Name the organelle that is the site of aerobic respiration.
Easy
47.The actual thickness of a leaf is 2 mm. In a diagram, the thickness is 50 mm. What is the magnification of the diagram? (Give your answer as a number, e.g., ×25)
Medium
48.A student measures the length of a palisade mesophyll cell in a photomicrograph as 75 mm. The magnification of the photomicrograph is ×2500. Calculate the actual length of the palisade mesophyll cell in micrometres (μm).
Medium
49.Explain how the structure of a root hair cell is adapted to its function of absorbing water and mineral ions from the soil.
Hard
50.A student measures the length of a bacterial cell in a diagram as 40 mm. The magnification is ×8000. What is the actual length of the bacterium in micrometres (μm)?
Medium
- A4 μm
- B5 μm
- C7 μm
- D6 μm
51.A student measures the length of a palisade mesophyll cell in a photomicrograph as 75 mm. The magnification of the photomicrograph is ×2500. Calculate the actual length of the palisade mesophyll cell in micrometres (μm).
Medium
- A30 μm
- B33 μm
- C27 μm
- D36 μm

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