Year 9 Term 1

Question 1

Prokaryotic cells

Answer 1

Much smaller than eukaryotic cells and are unicellular, with no nucleus e.g bacteria an blue-green algae

Question 2

Nucleus

Answer 2

Controls the activity of the cell

Question 3

Cytoplasm

Answer 3

In which most of the chemical reactions take place which are controlled by enzymes

Question 4

Cell membrane

Answer 4

Controls the passage of substances in and out of the cell

Question 5

Mitochondria

Answer 5

Where most energy is released in respiration

Question 6

Ribosomes

Answer 6

Where protein synthesis takes place

Question 7

Chloroplasts

Answer 7

Absorb light energy for photonsynthesis

Question 8

Permanent vacuole

Answer 8

Filled with sap

Question 9

Cell wall

Answer 9

Physical barrier protects against damage and osmotic lysis

Question 10

Capsule

Answer 10

Protection and helps bacteria to adhere to each other

Question 11

Cell-surfaced membrane

Answer 11

Permeable barrier controls entry and exit of chemicals

Question 12

Chromosomal dna

Answer 12

Genetic information for replication of the cell

Question 13

Plasmid

Answer 13

Process genes which aid the survival of bacteria

Question 14

Flagellum

Answer 14

Small whip-like tail for propulsion

Question 15

How big is a prokaryotic cell

Answer 15

Between 2 and 8 micrometers

Question 16

Stem cells

Answer 16

Single cells that can replicate themselves and differentiate into many cell types

Question 17

Eukaryotic cells

Answer 17

Cells which contain a true nucleus and other organelles which are enclosed within membranes e.g plant and animal cells

Question 18

Where are stem cells found in animals

Answer 18

In the umbilical cord, in bone marrow in adults,

Question 19

Where are stem cells found in animals

Answer 19

In the meristems of plants

Question 20

What are meristems and where are they found

Answer 20

They are found in the roots and shoots of a plant and they have the ability to divide over and over again to produce stem cells. The cells can continues to divide and grow taller and wider throughout its life

Question 21

How does growth happen in animals and plants

Answer 21

In animals it’s by increasing the number of cells but in plants it’s cell enlargements

Question 22

Cell differentiation in animals and plants

Answer 22

In animals most cells lose the ability to differentiate at an early stage and in plants many cells can differentiate

Question 23

Mitosis

Answer 23

Cell division in eukaryotic cells. The cell divides to produce 2 new identical copies

Question 24

cancer

Answer 24

Cancer cells must arise due to mutations in genes that control cell growth (mitosis), this leads to uncontrolled cell growth and results in a tumour

Question 25

diffusion

Answer 25

Random movement of particles from an area of high concentration to an area of low concentration i.e down a concentration gradient. Diffusion continues until particles are at an even concentration

Question 26

Where does diffusion take place

Answer 26

Lungs
Leaf
placenta

Question 27

What factors affect the rate of diffusion

Answer 27

Temperature
Concentration gradient
Surface area
Thickness of diffusion pathway

Question 28

An example of a short diffusion pathway

Answer 28

alveoli

Question 29

osmosis

Answer 29

The diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane that allows the passage of water molecules

Question 30

What is it called when an animal cell swells and bursts

Answer 30

lysis

Question 31

What is it called when an animal cell shrivels

Answer 31

crenation

Question 32

Why doesn’t a plant cell burst

Answer 32

Because it has a cell wall which prevents the cell from bursting

Question 33

What happens when a plant cell is placed in a concentrated solution

Answer 33

The water molecules will leave the cell and the cell membrane will pull away from the cell wall and is said to be plasmolysed

Question 34

What happens when a plant cell is placed in a dilute solution

Answer 34

The water molecules will enter the cell from outside and the cell will fill up with water but won’t burst, the cell is said to be turgid

Question 35

Active transport

Answer 35

Cell use active transport to transport substances across a partially permeable membrane against it’s concentration gradient i.e low to high using carrier protein and energy from respiration

Question 36

Where does this happen in living systems

Answer 36

Glucose can be reabsorbed into the kidney tumbles by active transport
Plants rely on active transport to obtain minerals through root hair cells.

Question 37

magnification

Answer 37

The number of times larger an image is compared with the real size of the object

Question 38

What is the equation for magnification

Answer 38

Size of image (I) / actual size of specimen (A)

Question 39

Key trick

Answer 39

Always measure your image in mm and most of the time the actual size of specimen is in micrometres