Biology Quiz

How do you calculate the actual size of a specimen using a scale bar?

• By measuring the scale bar and dividing by the magnification

• By measuring the specimen and multiplying by the magnification

• By measuring the scale bar and multiplying by the magnification

• By measuring the specimen and dividing by the magnification

Answer explanation

To find the actual size of a specimen, measure the scale bar and divide by the magnification. This gives the true size, as the scale bar represents a known length at the given magnification.

Which of the following is a characteristic of plant cells?

• Lack of a cell wall

• Presence of chloroplasts

• Absence of a nucleus

• Lack of mitochondria

Answer explanation

Plant cells are characterized by the presence of chloroplasts, which are essential for photosynthesis. In contrast, animal cells lack chloroplasts, have a flexible cell membrane, and possess other organelles like mitochondria.

What is a key difference between plant and animal cells?

• Plant cells have a cell wall, animal cells do not

• Animal cells have chloroplasts, plant cells do not

• Plant cells lack a nucleus, animal cells have one

• Animal cells have a cell wall, plant cells do not

Answer explanation

A key difference is that plant cells have a cell wall, which provides structure and protection, while animal cells do not have a cell wall. This distinction is crucial in understanding the structural differences between these two cell types.

What is the role of objective lenses in a microscope?

• To adjust the light

• To magnify the specimen

• To hold the slide

• To change the color

Answer explanation

The objective lenses in a microscope are crucial for magnifying the specimen, allowing for detailed observation. They do not adjust light, hold slides, or change color, making 'To magnify the specimen' the correct choice.

What is the effect of higher magnification on the field of view?

• It increases the field of view

• It decreases the field of view

• It has no effect

• It changes the color

Answer explanation

Higher magnification narrows the view of the specimen, focusing on a smaller area. This results in a decreased field of view, making it harder to see the overall context of the sample.

What part of the cell is responsible for containing the genetic material?

• Cell membrane

• Cytoplasm

• Nucleus

• Vacuole

Answer explanation

The nucleus is the part of the cell that contains the genetic material, including DNA. It acts as the control center for cell activities and is essential for heredity and cellular function.

Which of the following is a function of the cell membrane?

• Provides energy

• Stores genetic material

• Regulates entry and exit of substances

• Synthesizes proteins

Answer explanation

The cell membrane regulates the entry and exit of substances, maintaining homeostasis. It acts as a selective barrier, allowing essential nutrients in and waste products out, which is crucial for cell function.

What is the magnification if the size of the image is 10 mm and the actual size is 1 mm?

• 10

• 100

• 1

• 0.1

Answer explanation

Magnification is calculated as the size of the image divided by the actual size. Here, it is 10 mm (image size) divided by 1 mm (actual size), which equals 10. Therefore, the correct answer is 10.

If a scale bar in a micrograph measures 5 cm, what is the magnification if the scale bar represents 0.1 mm?

• x50

• x500

• x5

• x5000

Answer explanation

To find magnification, divide the scale bar length by the actual size it represents. Here, 5 cm (50 mm) divided by 0.1 mm equals 500. Thus, the magnification is x500.

If a photograph of a cell is magnified x500 and the scale bar measures 5 cm, what is the actual size represented by the scale bar?

• 0.1 mm

• 1 mm

• 10 mm

• 0.01 mm

Answer explanation

To find the actual size, divide the scale bar length by the magnification: 5 cm / 500 = 0.01 cm, which is 0.1 mm. Thus, the correct answer is 0.1 mm.