Key Concepts in Biology

Question 1

What is an electron microscope?

Answer 1

A microscope that can magnify at much higher resolution than a light microscope

Question 2

How can total magnification be calculated?

Answer 2

Total magnification = eyepiece lens x objective lens

Question 3

What is the magnification triangle?

Answer 3

image height = magnification x object height

Question 4

What is meant by an instruments resolution?

Answer 4

An instruments resolution is the instruments ability to distinguish between different light

Question 5

What features do animal cells have?

Answer 5

Nucleus
Cell membrane
Cytoplasm
Ribosomes
Mitochondria

Question 6

What features do plant cells have?

Answer 6

Nucleus
Cell membrane
Cytoplasm
Ribosomes
Mitochondria
Cell wall
Large Vacuole
Chloroplasts

Question 7

What features do plant cells have that animal cells don’t?

Answer 7

Cell wall
Large Vacuole
Chloroplasts

Question 8

How are sperm cells adapted to their function?

Answer 8

They have a haploid nucleus, a mid piece containing many mitochondria, a long flagellum (tail)

Question 9

How are egg cells adapted to their function?

Answer 9

They have cytoplasm containing many mitochondria, a haploid nucleus and are large

Question 10

How are ciliated epithelial cells adapted to their function?

Answer 10

Long and thin with tiny hairs on one end

They also have a lot of mitochondria

Question 11

Name the common features of a bacteria

Answer 11

No nucleus
flagellum
cell wall
cell membrane

Question 12

Why are bacteria classed as prokaryotic?

Answer 12

Because they do not have a nucleus

Question 13

What is the difference between eukaryotic and prokaryotic cells?

Answer 13

Prokaryotic cells don’t have a nucleus, whereas eukaryotic cells do

Question 14

Where are enzymes normally found?

Answer 14

Stomach, intestines, saliva etc

Question 15

What is an enzyme?

Answer 15

An enzyme is a protein. They are also biological catalysts

Question 16

Why are enzymes useful?

Answer 16

Because they speed up reactions, which is useful for life processes

Question 17

How can you test for starch in foods and what do positive and negative results look like?

Answer 17

Add iodine

Positive: Blue/Black
Negative: Brown

Question 18

How can you test for reducing sugars in foods and what do positive and negative results look like?

Answer 18

Add Benedict’s reagent and heat in a water bath.
Blue = little sugar
Red = lots of sugar

Question 19

How can you test for lipids in foods and what do positive and negative results look like?

Answer 19

Shake substance in ethanol, then add water.

Milky colour = lipids
Clear = no lipids

Question 20

How can you test for proteins in foods and what do positive and negative results look like?

Answer 20

Add potassium hydroxide (alkaline). Add copper(II) sulfate
Blue = negative
Purple = positive

Question 21

Define Diffusion.

Answer 21

The net movement of particles from an area of high concentration to an area of low concentration.

Question 22

Define Osmosis.

Answer 22

The net movement of water particles across a partially permeable membrane from an area of higher water concentration to an area of lower water concentration.

Question 23

Define Active transport.

Answer 23

The movement of particles across a membrane against the concentration gradient.

Question 24

Which is the only one that requires energy?

Answer 24

Active transport.

Question 25

What vegetable did you use to carry out the osmosis practical?

Answer 25

Potato

Question 26

The cube of potato weighed 15.1g before the experiment and 13.6g at the end. Calculate the % change in mass.

Answer 26

11.02%