Chapter 1- cell structure and transport

Question 1

What are chloroplasts ?

Answer 1

Green part of the plant, they contain chlorophyll which absorbs light for photosynthesis

Question 2

What is a eukaryotic cell?

Answer 2

Animal and plant cells

They all have cell membrane, cytoplasm and genetic material in a nuclear

Question 3

What is a prokaryote?

Answer 3

Bacteria- a single-celled living organism

May contain small bits of DNA

Question 4

What are plasmids ?

Answer 4

Code for specific features such as antibiotic resistance

Question 5

How are nerve cells specialised to carry signals around the body ?

Answer 5

1) they have lots of dendrites which make connections to other nerve cells
2) and axon to carry nerve impulses from one place to another

Question 6

How are muscle cells specialised?

Answer 6

1) They contain special proteins that can slide over each other and make the fibres contract
2) they store glycogen to transfer energy needed for fibres to contract

Question 7

What are root hair cells ?

Answer 7

Root hair cells are found near the tips of growing roots

They help take minerals and water up into the plant more efficiently

Question 8

What do root hair cells do ?

Answer 8

They greatly increase the surface area so that more water can move up the cell
They have a large permanent vacuole that helps speed up the movement of water by osmosis
Mitochondria that help transport energy

Question 9

What are photosynthetic cells ?

Answer 9

Cells that help plants make their own food by photosynthesis

Question 10

How are photosynthetic cells adapted ?

Answer 10

They contain specialised green structures called chloroplasts that trap light
Placed in leaves so can absorb as much light as possible
Large permanent vacuole to keep the cell rigid

Question 11

What are Xylem cells?

Answer 11

A transport tissue in plants that carry water and mineral ions from the roots to leaves and shoots higher up the plant

Question 12

How are xylem cells adapted?

Answer 12

The xylem cells die and form long hollow tubes that allow water and mineral ions to move easily up them
Spiral rings of login make them stand tall and strong so they can hold the pressure of water

Question 13

What are phloem cells ?

Answer 13

A specialised transport tissue that can carry food made by photosynthesis around the body

Question 14

How has a phloem cell adapted ?

Answer 14

The cell walls between cells break down to form special sieve plates. These allow water to carry dissolved food freely up and down the tubes

Question 15

What is diffusion ?

Answer 15

The spreading out of gas particles over a substance, they move from a high concentration to a low concentration

Question 16

How is the rate of diffusion effected ?

Answer 16

An increase in temperature means that the particles in a gas solution move around quickly
If there is a small difference in concentration between 2 areas then diffusion will happen slowly

Question 17

Where does diffusion happen?

Answer 17

Diffusion happens over the cell membrane

An example is oxygen from your lungs pass to your red blood cells by diffusion

Question 18

What are partially permeable membranes ?

Answer 18

Membranes that only let some types of particles through

Question 19

What is osmosis ?

Answer 19

Type of diffusion where only water moves across a partially permeable membrane from a dilute solution to a concentrated solution

Question 20

What does isotonic mean?

Answer 20

When the solution outside the cell is the same as the internal concentration

Question 21

What does hypertonic mean?

Answer 21

When the solution outside the cell is higher then the concentration inside a cell

Question 22

What does hypotonic mean ?

Answer 22

When the solution outside the cell is lower concentration then the internal concentration

Question 23

Osmosis in plants

Answer 23

Plants rely on osmosis to help support their stem and leaves. More water moves into plant cells by osmosis the pressure of water is known as turgid which helps the plant stay rigid

Question 24

What is active transport?

Answer 24

Allows cells to move substances from a low concentration to a high concentration through a semi permeable membrane

Question 25

Why do we need active transport?

Answer 25

It helps us move substances we need such as sugars and ions to cells so they can absorb them.

Question 26

Example of active transport in plants

Answer 26

The plant needs mineral ions found in the soil that are usually in very dilute conditions, to get them into the plant with a higher concentration of much use active transport