B-1 Cells

Question 1

Nucleus

Answer 1

Organelle and centre of most cells (Eukaryotic) which contains genetic information.

Question 2

Cytoplasm

Answer 2

A water based gel found in cells that most organelle are found in.

Question 3

Cell membrane

Answer 3

The membrane around a cell that controls what comes in and out of it.

Question 4

Mitochondria

Answer 4

The powerhouse of the cell

Where respiration takes place

Question 5

Ribosome

Answer 5

The sight of protein synthesis in a cell

Question 6

Cell wall

Answer 6

The structure around plant cells to make them stronger

Question 7

Vacuole

Answer 7

Large organelles found in cells containing fluids or waste

Question 8

Chloroplast

Answer 8

The organelles where photosynthesis takes place

Question 9

Eukaryotic cells

Answer 9

Membrane bound organelles
Multi cellular
Mitochondria present

Question 10

Prokaryotic cells

Answer 10

Single cells
No membrane bound organelles
No mitochondria

Question 11

Plasmid

Answer 11

A double stranded DNA that is able to replicate chromosomal DNA

Question 12

Order of magnitude

Answer 12

Numbers written timesed by the power of 10. Used to show the size of cells

Question 13

Nerve cell adaptations

Answer 13

Stretched out ends.

Long body to reach other cells

Question 14

Muscle cell adaptations

Answer 14

Allows them to communicate

Question 15

Sperm cell adaptations

Answer 15

Long tail to swim.

Head to burrow into egg.

Question 16

Root hair cells adaptations

Answer 16

Large surface area to speed up osmosis.

Question 17

What are chromosomes

Answer 17

• Chromsomes contrair genetic information
• Carry a large number of genes
• Travel in pairs

Question 18

Describe the stages of the cell cycle

Answer 18

Growth and DNA replication

• DNA is spread out along long strings
• Before it decides it increases in size and increases amount of subcelluar structures
• Then DNA is duplicated.

Mitosis

• The chromosomes are lined up at the centre of the cell and pulled apart to opposite ends
• Membranes form around the sets of chromosomes. These form the nucleus.
• Lastly the cyctoplasm and cell membrane divide

Question 19

What are stem cells

Answer 19

• Stem cells are undifferentiated (unspecialised) cells

- They can differentiate into other form of cell dependant on the need

Question 20

Where can stem cells be found

Answer 20

Stem cells can be found in Embryos - can specialise widely

Human bone barrow- less variety in what they can change into

Question 21

What are the benefits of stem cells

Answer 21

• Stem cells can be used to cure diseases.
• Embryonic stem cells can be transferred to sick people e.g diabetes
• There is no risk of rejection as it adapts to people
• Can produce identical plants

Question 22

What are the disadvantages of stem cells

Answer 22

• Some people feel human embryos should unit be used as they are potential human life
• Embryos cannot consent
• It can be very expensive

Question 23

What is diffusion

Answer 23

• Diffusion is the spreading out of particles from an area o high concentration to low concentration across a concentration gradient
• The higher the gradient the faster the rate
• The higher the temperature the faster the rate

Question 24

What type of substances can diffusion take place

Answer 24

• Gasses and liquids as they have free particles that can move

Question 25

How do cell membranes use diffusion

Answer 25

- Cell membranes hold the cell together - They also let things in and out through diffusion - Only very small molecules can diffuse through this - The larger the surface area of the membrane the faster the division rate

Question 26

What is osmosis

Answer 26

- Osmosis is the moment of water across a partially permeable membrane from an area of high water concentration to an area of low water concentration - It is a type of diffusion

Question 27

What is active transport

Answer 27

-Active transport IS the movement of substances against a concentration gradient- using ATP energy

Question 28

Why is active transport needed

Answer 28

- Active transport is needed as for example trees need minerals that are in lower concentrations in the soil. It has to get these through this - Humans also need it in the gut where there is a lower concentration of nutrients but a higher concentration in the blood. We have to access this glucoseH and we do so through active transport

Question 29

How does surface area to volume ratio influence rate of reactions

Answer 29

- The higher the surface area to volume ratio the faster the rate of reaction - IT allows for the faster exchange of substances between organisms e.g. cells

Question 30

What are some adaptations in cells to increase surface area to volume ratio and increase rate of relations between cells

Answer 30

- Thin cell membrane for fast diffusion - Large surface area - Large amounts of blood vessels - Gas exchange surfaces

Question 31

How have the alveoli in the lungs adapted for fast gas exchange

Answer 31

- Alveoli - Huge surface area- 75m2- large SA/V ratio - Moist lining for dissolving gasses - Very thin walls - Good blood supply

Question 32

How has the Villli in the small intestine adapted for fast gas exchange

Answer 32

- Villi - Increase the surface area and food is absorbed more quickly into the blood - Millions present _ single thin layer _ very good blood supply

Question 33

How are leaves sectored to aid fast gas exchange

Answer 33

- The underneath of the leaf has stomata where co2 can come through - Oxygen and water can diffuse out of the stomata - Guard cells can protect the stomata - Shape allows for large SA/V ratio - Walls of cells form another exchange surface

Question 34

How hace gills on fish adapted for fast gas exchange

Answer 34

- Each gill has lots of thin plates called gill filaments which have large surface areas - Gill filaments have many lamellae increasing surface area even more - Lamellae have lots of blood capliedries - Thin surface to allow for fast diffusion - Concentration of oxygen always higher in water