R2101 2.1 Describe structure of plant cells, components and tissues

Question 1

What is tissue?

Answer 1

Collection of specialised cells carrying out a function e.g. Xylem

Question 2

What is an organ?

Answer 2

A group of tissue carrying out a function e.g. leaf producing sugars for plant

Question 3

Cell wall function (3)

Answer 3

1. Made of cellulose. Protects and contains cells contents
2. Permeable to gases and liquids
   3.Structural support and protection. Cell walls thickens by addition of cellulose, then by addition of lignin hardens and becomes woody.

Question 4

Cell Membrane function

Answer 4

Semi -permeable. Controls movement of substances in and out of the cell i.e. sugar, food, minerals

Question 5

Cytoplasm function

Answer 5

1. Jelly like substance where organelles are located. Allows dissolved substances to move around the cell and take part in chemical reactions
2. Has network of protein strands which hold cell components in place and prevents them sinking tot he bottom of the cell via gravity

Question 6

Nucleus function (2)

Answer 6

1. Control centre of the cell
2. Produces DNA, manufactures RNA

Question 7

Mitochondria function

Answer 7

Release energy by the process of respiration

Question 8

Chloroplasts function (3)

Answer 8

1. Contains chlorohpyll
2. Involved in the production of sugar by photosynthesis
3. Short term storage of sugar in the form of starch
4. Found mainly in leaves, sometimes stems, never roots

Question 9

Endoplasmic Reticulum function

Answer 9

Mesh of membranes that enables transport of chemicals within the cells and links with the cell membrane and cell surface

Question 10

Vacuole function

Answer 10

1. Contains dilute sugar, nutrients, pigments and waste products.
2. Main function storage of waste products and maintaining cell shape by outward pressure

Question 11

What is protoplasm?

Answer 11

The collective name for all the living matter in a cell, including membrane, nucleus and cytoplasm

Question 12

What is the intercellular space?

Answer 12

Where three cells join there is space which allows gases to diffuse around the cells

Question 13

What is middle lamella?

Answer 13

Thin layer made of pectin gluing together adjectent cells

Question 14

What is plasmodesmata?

Answer 14

Microscopic tubes which perforate cells walls and make connections to adjacent cells

Question 15

Where does each of the following take place:

i) photosynthesis

ii) control of cell turgor

iii) up-take (absorption) of minerals

iv) aerobic respiration

Answer 15

i) chloroplast

ii) vacuole

iii) cell membrane

iv) mitochondrion

Question 16

Name the cell component that carries out the following functions:

i) limits cell expansion

ii) water storage

iii) suspends cell organelles

Answer 16

i) cell wall

ii) vacuole

iii) cytoplasm

Question 17

Where does cell division and growth occur in plants?

Answer 17

Growing points or meristems

apical meristem (tip of bud, root)
lateral meristem = axillary bud

Question 18

Describe cell division.

Answer 18

duplication of the genetic material and its equal distribution to each of two ‘daughter’ cells
usually preceded by cell growth, so that when the cell divides, the two daughter cells are essentially similar to the parent cell
in mitosis the daughter cell ends up with exactly the same number of chromosomes as the parent cell
takes place when an organism grows, replaces old cells or reproduces asexually

Question 19

Describe where cell division is located within the plant

Answer 19

Cell division is only located in certain regions of the plant:

1) apical meristems are the sites of primary lengthwise growth located at the tips of shoots and roots.

2) Lateral meristems are found in the cambium layer immediately below the bark in woody plants which allow stems and roots to increase in girth, known as secondary growth

Question 20

Describe the process which causes plant cells to expand.

Answer 20

Water passes into the cell by osmosis.

As water enters, turgor pressure inside the cell presses outwards against the cell membrane and stretches it and therefore expands the cell.

Question 21

How do new plants grow (2)

Answer 21

1. Mainly by creating new cells by cell division
2. Incresing the size of existing cells

Question 22

What is a meristem?

Answer 22

Area of a plant where cell division takes place

Question 23

What is mitosis?

Answer 23

Divison of parent cells into two daughter cells

Question 24

Which types of plants can experience secondary thickening?

Answer 24

Dicotyledons and Gymnosperms

Question 25

How do moncots thicken?

Answer 25

As plant grows the existing leave bases are compressed and dry out forming a hard outer layer. There is no secondary thickening

Question 26

Where does primary growth take place?

Answer 26

Apical meristems

Question 27

Where does secondary growth take place?

Answer 27

Lateral meristems