Cell structure 2.0

Question 1

how is a sperm cell specialised to carry out its function? (4 adaptations)

Answer 1

• head contains genetic material for fertilisation in a haploid nucleus.
• acrosome in head contains enzymes so that a sperm can penetrate an egg’s cell membrane
• middle piece is packed with mitochondria to release energy needed to swim
• flagellum enables sperm cell to swim

Question 2

how is an egg cell specialised to carry out its function? (3 adaptations)

Answer 2

• haploid nucleus contains genetic material for fertilisation.
• cytoplasm contains nutrients for growth of early embryo.
• cell membrane changes after fertilisation by a single sperm so that no more sperm can enter.

Question 3

what does haploid mean?

Answer 3

-sex cell (gamete) that contains one set of chromosomes

Question 4

what is a gamete?

Answer 4

-sex cell

Question 5

how many chromosomes does a human gamete contain?

Answer 5

23 chromosomes

Question 6

how is a ciliated epithelial cell specialised to carry out its function? (1 adaptation)

Answer 6

-cilia on the surface to move fluids and particles along

Question 7

why do we need microscopes? and what is their purpose?

Answer 7

• to study most cells.

- to produce magnified images.

Question 8

purpose of light microscopes? (2)

Answer 8

• used to study living cells

- for regular use when relatively low magnification and resolution is enough

Question 9

purpose of electron microscopes? + a disadvantage

Answer 9

• provide higher magnifications and higher resolution images
• cannot be used to view living cells

Question 10

how have microscopes improved over time?

Answer 10

-optical quality of lenses increased, and therefore the magnification of light microscopes has increased

Question 11

what do compound microscopes use? what are they called?

Answer 11

• uses two lenses to magnify the specimen

- the eyepiece and an objective lens.

Question 12

microscope magnification equation:

Answer 12

I = A x M

image size = actual size of object x magnification

Question 13

what is resolution/ resulting power?

Answer 13

the ability to see two points as two points, rather than merged into one

Question 14

how do electron microscopes differ from light microscopes?

Answer 14

-use a beam of electrons instead of beams or rays of light.

Question 15

why can living cells not be examined with an electron microscope? (2)

Answer 15

• because the specimens/samples are placed in a vacuum

- beam of electrons kills the organism

Question 16

what is an order of magnitude?

what do you do when you ought to increase a number by one order of magnitude?

Answer 16

• when two numbers share the same power of 10

- multiply it by 10 OR increase its power by one