Topic 1 Cells

Question 1

How are eukaryotic cells defined?

Answer 1

They have a nucleus

Question 2

What organelles are present in an animal cell?

Answer 2

Nucleus, cell membrane, mitochondria and ribosomes

Question 3

What organelles are present in a plant cell

Answer 3

Nucleus, cell membrane, cell wall, chloroplasts, mitochondria, vacuole and ribosomes

Question 4

What organelles are present in a bacteria cell?

Answer 4

Chromosomal DNA, Plasmid DNA, cell membrane, ribosomes and flagella

Question 5

Function of the nucleus

Answer 5

Contains DNA (enclosed in a nuclear membrane) coding for specific proteins needed to build new cells

Question 6

Function of the cytoplasm

Answer 6

• Liquid substance in which chemical reactions occur.
• Contains enzymes (biological catalysts, i.e. proteins that speed up the rate of reaction).
• Organelles are found in it

Question 7

Function of the cell membrane

Answer 7

Controls what enters and leaves the cell

Question 8

Function of the mitochondria

Answer 8

The site of aerobic respiration reactions which provide energy for the cell

Question 9

Function of the ribosomes

Answer 9

• Where protein synthesis occurs.
• Found on a structure called the rough endoplasmic reticulum.

Question 10

Function of the chloroplasts

Answer 10

• Where photosynthesis takes place, providing food for the plant
• Contains chlorophyll pigment (which makes it green) which harvests the light needed for photosynthesis.

Question 11

Function of the permanent vacuole

Answer 11

• Contains cell sap
• Found within the cytoplasm
• Improves cell’s rigidity

Question 12

Function of the cellulose cell wall

Answer 12

Provides strength and structure to the cell

Question 13

Chromosomal DNA (circular)

Answer 13

As bacterial cells have no nucleus, it floats on the cytoplasm

Question 14

Function of plasmids

Answer 14

Small rings of DNA - code for extra genes to those provided by chromosomal
DNA

Question 15

Function of flagella

Answer 15

Long, thin ‘whip-like’ tails attached to bacteria that allow them to move

Question 16

How are sperm cells adapted to their function

Answer 16

• Streamlined head and long tail to aid swimming
• Many mitochondria (where respiration happens) which supply the energy to allow the cell to move
• The acrosome (top of the head) has digestive enzymes which break down the outer layers of membrane of the egg cell
• Haploid nucleus - the word haploid simply means that it has 23 chromosomes, rather than the 46 that most other body cells have

Question 17

How are egg cells adapted to their function

Answer 17

• Surrounded by a special cell membrane which can only accept one sperm cell (during fertilisation) and becomes impermeable following this
• Lots of mitochondria to provide an energy source for the developing embryo
• Large size and cytoplasm to allow quick, repeated division as the embryo grows

Question 18

How are ciliated epithelial cells adapted to their function

Answer 18

• Long, hair-like processes called cilia waft bacteria trapped by sticky mucus
(produced by nearby goblet cells) down to the stomach, where they are killed
by the stomach acid. This is one of the ways our body protects against illness.