R2101 2.1 Describe structure of plant cells, components and tissues Flashcards
(27 cards)
What is tissue?
Collection of specialised cells carrying out a function e.g. Xylem
What is an organ?
A group of tissue carrying out a function e.g. leaf producing sugars for plant
Cell wall function (3)
- Made of cellulose. Protects and contains cells contents
- 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.
Cell Membrane function
Semi -permeable. Controls movement of substances in and out of the cell i.e. sugar, food, minerals
Cytoplasm function
- Jelly like substance where organelles are located. Allows dissolved substances to move around the cell and take part in chemical reactions
- Has network of protein strands which hold cell components in place and prevents them sinking tot he bottom of the cell via gravity
Nucleus function (2)
- Control centre of the cell
- Produces DNA, manufactures RNA
Mitochondria function
Release energy by the process of respiration
Chloroplasts function (3)
- Contains chlorohpyll
- Involved in the production of sugar by photosynthesis
- Short term storage of sugar in the form of starch
- Found mainly in leaves, sometimes stems, never roots
Endoplasmic Reticulum function
Mesh of membranes that enables transport of chemicals within the cells and links with the cell membrane and cell surface
Vacuole function
- Contains dilute sugar, nutrients, pigments and waste products.
- Main function storage of waste products and maintaining cell shape by outward pressure
What is protoplasm?
The collective name for all the living matter in a cell, including membrane, nucleus and cytoplasm
What is the intercellular space?
Where three cells join there is space which allows gases to diffuse around the cells
What is middle lamella?
Thin layer made of pectin gluing together adjectent cells
What is plasmodesmata?
Microscopic tubes which perforate cells walls and make connections to adjacent cells
Where does each of the following take place:
i) photosynthesis
ii) control of cell turgor
iii) up-take (absorption) of minerals
iv) aerobic respiration
i) chloroplast
ii) vacuole
iii) cell membrane
iv) mitochondrion
Name the cell component that carries out the following functions:
i) limits cell expansion
ii) water storage
iii) suspends cell organelles
i) cell wall
ii) vacuole
iii) cytoplasm
Where does cell division and growth occur in plants?
Growing points or meristems
apical meristem (tip of bud, root) lateral meristem = axillary bud
Describe cell division.
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
Describe where cell division is located within the plant
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
Describe the process which causes plant cells to expand.
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.
How do new plants grow (2)
- Mainly by creating new cells by cell division
- Incresing the size of existing cells
What is a meristem?
Area of a plant where cell division takes place
What is mitosis?
Divison of parent cells into two daughter cells
Which types of plants can experience secondary thickening?
Dicotyledons and Gymnosperms
