B4 Flashcards
What is respiration?
The process of transferring energy from the breaking down of glucose
Plants make their own gluclose through respiration whearas animals get it by breaking down the biomass they get when eating other organisms
What are the two types of respiration?
Aerobic respiration and anaerobic respiration
What is anaerobic respiration?
1.Takes place when there is enough oxygen available
2.Breaks down glucose and combines the products with oxygen to get carbon dioxide and water
3.Most efficient way of transferring energy from glucose
4.Reversed reaction of photosynthesis
5.Glucose + oxygen => Carbon Dioxide + water
What is anaerobic respiration?
1.Takes place when there is small amout of oxygen available
2.Transfers less energy (2 molecules of ATP)
3.Sometimes lactic acid is produced(what gives us cramps)
What is the CELL CYCLE and what is it used for?
– Makes new cells for growth and repair
– Body cells in multicellular organisms divide to produce new cells as a part of a series of stages called the cell cycle
– Used to help organisms grow or replace damaged cells
Interphase and Mitosis
(The two main stages of the cell cycle)
Interphase
- In a cell thats not dividing the DNA is spread out in long strings
- Before cell division, the amount of mitochodria and ribosomes has to increase
- Then DNA is duplicated, so theres a copy for each new cell
Mitosis
- The chromosomes line up at the centre of the cell, The two arms of each chromosome go to opposite ends of the cell
- Membranes then form around each of the sets of chromosomes, then these become the nuclei of the two new cells-THE NUCLEUS HAS DIVIDED
- the cytoplasm and cell membran divide, the cell has porduced two daughter cells, they contain the exact same chromosomes, they are genetically identical
What happens during meiosis?
- meiosis is cell division
- Produces gametes
- Division 1
1. Goes through interphase(duplicates DNA). One arm of each x shaped chromosome is an exact same as the other arm
2.The chromosomes line up in pairs, one chromosome in each pair came from the organisms mother and the other from the father
3.The pairs are pulled apart, so each new cell ends up with one chromosome from each pair
4.The chromosome number of each new cell will be half of the original cell. Each cell will be a mixture of the father and mothers chromosomes-important to mix because it creates genetic variation
in the offspring - Division 2
5.The chromosomes line up again then the arms of the chromosomes are pulled apart
6.You then get 4 gametes-each only has one set of chromosomes. They are genetically different
What are stem cells?
Cells that are able to differentiate into different types of cells
What are auxins?
- Plant growth hormones
- Control and coordinates growth at the tips of shoots and roots
- SHOOTS are positively PHOTOTROPHIC(grows towards light) and negatively GRAVITRPOHIC(grows away from gravity)
- ROOTS are positively GRAVITROPIC and negatively PHOTOTROPIC
- high auxin means=more stem growth but less root growth
What other hormones Are involved in plant growth?
- GIBBERELLINS- controls germination and flowering
2.ETHENE- stimulates shedding of leaves and ripening of fruits
What is phototropism?
- When a plant responds to a light stimulus
- positive tropism- plants grow towards stimulus
- negative tropism-plants grow away from stimulus
- stems grow towards light
- roots grow away from light
What is geotropism?
When the plant responds to gravity
What is giberellin?
- Controls cell elongation, influences germination(The beginning of the growth of a seed into a seedling)
- can end seed dormancy
