Semester 1-3 BIO Topics Grade 12 (EXAMS)
How do plants obtain water for photosynthesis?
- By the roots from the soil, and then is transported through the xylem vessels into the leaves
What is the function of chlorophyll?
- to absorb light that provides energy for photosynthesis to take place
Chlorophyll
-A complex organic molecule -Contains magnesium -is a green pigment because it absorbs blue and red light but reflex green light
Breathing roots
-Allows roots system to obtain air Example ; plants found in the black mangrove
dermal tissue
-Also called the epidermis -Has a protective function [outer layer]
Photosynthesis occurs in a series of steps that are controlled by what
-Enzymes
Prop roots
-Extend from stems and branches to stabilize a plant Example, red mangrove, and corn
Lignin
-In the walls of the xylem vessels -Helps strengthen the leaf
mesophyll layer
-Located between the upper and lower epidermis -Contains chloroplast to carry out photosynthesis -Cells in these layers also strengthen the leaves when turgid Palisade mesophyll contains elongated cells
Vascular bundles
-Located within the mesophyll -consist of the xylem and phelom vessels
What is the difference between photosynthesis and respiration?
-Photosynthesis only occur in the day -Respiration takes place during the day and night
At night
-Respiration takes place before photosynthesis does not -Oxygen is going to diffuse into the plant -Carbon dioxide diffuses out of the plant
What form is the food usually in?
-Simple sugar called glucose
Butterous roots
-Support large trees Example, almond or mango tree
Epidermis
-The outer layer of the leaf -Protected from damage and excessive water loss -The upper epidermis is covered with waxy cuticle, which reflects heat to reduce water loss -do not have chloroplast
What is photosynthesis?
-The process by which plan use sunlight to combine carbon dioxide and water to make their own food
In dim light
-The rate of respiration may be equal to the rate of photosynthesis -No net gas exchange. -This occurs because carbon dioxide produced by respiration is being used up by photosynthesis.
ground tissue
-They are packing cells (carrying parenchyma) -Between the dermis and the vascular bundle -Can carry out photosynthesis -provide support and store food
Why are the leaves suitable for photosynthesis?
-They contain tiny paws through which carbon dioxide diffuse and itself also continues the organelle called chloro chloroplast
The stomata
-Usually open during the day -Water passes into the guard cells by osmosis. -This makes them bend so the stoma opens
What happens next?
-Water moves across the root cortex from cell to cell by osmosis until it enters the xylem vessel -from one area to another what is then drawn up the stem to the leaves
Chloroplast
-an over shaped organelle -Contains a system of thylakoid membrane -Provide a large service area for absorption of light energy
Importance of transpiration
-evaporation of water helps cool the plant -Provides leaves with water for photosynthesis -Prevent wilting -Transports minerals that are use used for cellular reaction and proteinsynthesis
Rihizomes
-horizontal underground stems that play a roll in food storage and asexual reproduction example; ginger
What is the main site of photosynthesis of the plant?
-leaves
Where is the phloem and xylem located?
-phloem located towards the outside -xylem located towards the inside of the stem
The Importance of Photosynthesis
-plants convert light energy into chemicals, energy stored in food molecules - This energy is passed the animals through the food chain - Produce oxygen, which is released into the atmosphere where I can be used up by other animals for respiration
Guard cells
-spores in the epidermidis, surrounded by guard cells -Guard cells open and close the stomata -These cells contain chloroplast
Light independent reaction
-takes place in the stroma of the chloroplast -ATP produced in the light dependent reaction, provide the energy use to produce carbohydrate (starch) from carbon dioxide molecules
Light dependent reaction
-takes place in the thylakoid membrane of the chloroplast -Light energy absorbs by chlorophyll molecules and split water to produce oxygen gas -Raises electrons and hydrogen ions
Glucose produced in photosynthesis is used to
-used in respiration for the production of energy -Convert to starch for storage in the roots and stems or stored in the starch granules in the leaf
Adoption adoption leaves for photosynthesis
1. Contains air spaces - they are found in the spongy mesophyll, and also provided a large surface area for the diffusion of gases. 2. contains a stole - it allows gaseous exchange between the inside of the leaf and the external environment. 3. Leaves are thin - allows short, diffusion distance for gases to go in and out of things.
What is the chemical equation for photosynthesis?
6CO2 + 6H2O + light energy = C6H12O6 + 6O2
What does hydrogen ion produce?
ATP adenosine triphophate
What does the shoot system consist of?
Above ground Leaves Bud Stem Flower Fruit
Runners
Above ground stems from which new plants can grow Example; grass
Products that are formed by photosynthesis
Carbon dioxide + water ——> glucose + sunlight -glucose -Oxygen - Energy
What is chloroplast?
Chloroplast in the leaf cells contains a green pigment called chlorophyll
Example of roots
Clasping roots -allows veins and epiphytes to grow on fences and trees. Example; monkey tamarin, and passionfruit
The cells in these parts of the plant contains chloroplast, which contains chemical such as what
Enzymes Chlorophyll [They are necessary for the reaction to take place.)
What are the several types of tissue that the leaf consist of?
Epidermis Mesophyll layers Vascular bundles Spongy mesosphyll Guard
Where does roots absorb water from?
From the soil by osmosis
Where is chloroplast found
In the palisade, mesophyll, spongy and guard cell of a leaf
What are the main sites of water loss during the process process of transpiration?
Leaves
Vascular tissue
Made up of a vascular bundle Consist of xylems vessels, and phloem
What are the seven major elements required by plants called macro nutrients
Phosphorus Nitrogen Sulfur Iron Magnesium potassium calcium
importance of light
Provides energy for photosynthesis to take place
The stem can be modified to perform different functions list three examples
Rihizomes Tubers Runners
What are the two men systems in a plant?
Root and shoot
Bright light
The rate of photosynthesis is greater than the rate of respiration - The oxygen will diffuse all of the leaves and carbon dioxide diffuses into the leaf - The leaf produce more oxygen than it needs for respiration
Where does the water evaporates through?
The stomata and a small amount also evaporates through the waxy cuticle
Where are minerals absorbed?
They are absorbed by the roots of the plants by active transport
Root system
Underground Mostly consist of root
Tubers
Underground, swollen, stems that store foods Example; potato and carrots
The following factors effect the rate of photosynthesis
Water availability Light intensity Carbon dioxide concentration Temperature Presence of chlorophyll
What are some of the small amounts of minerals required
Zinc maganese Cobalt Copper Chlorine Silicone
Farmers can amend the soil by adding natural manure or compost. What is the artificial fertilizer called
[NPK] nitrogen, phosphorus, and potassium
What is the cambium?
a layer of tissue that grows between xylem and phloem
What is ATP?
adenosine triphosphate A chemical used by cells to form energy . Therefore, during this stage light energy is converted to chemical energy in the form of ATP
What are the requirements for photosynthesis?
carbon dioxide, water, and sunlight
What are the three main types of tissue in plants?
dermal, ground, vascular
What are the two stages of photosynthesis?
light dependent and light independent
What are the two main types of roots?
taproots and fibrous roots
Bulbs
the round parts of some plants that are underground Example; onions and garlic
