B4 COPY Flashcards
What is respiration?
Transferring energy from the breakdown of glucose
- animals produce glucose when breaaking down biomass
- plants make glucose by photosynthesis
In plants, where does aerobic respiration take place?
In the mitochondria as it contains the enzymes required for aerobic respiration.
What is the formula for aerobic respiration?
Glucose+oxygen>carbon dioxide+water
What is anaerobic respiration?
Transferring energy without oxygen
-takes place in the cytoplasm
What is the formula for anaerobic respiration?
Glucose > Lactic Acid
Some organisms produce ethanol and carbon dioxide
What examples of anaerobic respiration are there?
- Human cells respire anaerobically when doing exercise
- some bacteria respire anaerobically to survive
What is the job of the cell cycle?
Making new cells for growth and repair
What happens at the interphase?
Before the cell divides, it has to grow
It then duplicates its DNA so there is one copy for each new cell.
What happens at the mitosis?
Chromosomes line up and are pulled apart by the cell fibres
-arms of each chomosome go to opposite ends of the cell
Membranes form around the chromosmes-become the nuclei of the 2 cells
Then the cytoplasm and membrane then divide, producing daughter cells-idnetical to parent cell
What are light microscopes?
Work by passing light through the specimin
-they let us see things like the nuclei and chloroplasts
What are electron miscroscopes?
Use electrons rather than light
- higher magnification and resolution than light microscopes
- allow us to see internal structure of things like chloroplasts
What is the equation for total magnification?
eyepiece lens magnification x lens magnification
What happens during sexual reproduction?
Father and mother gametes pair up to form a zygote
- the zygo undergoes cell division and develops into an embryo
- the embryo inherits characteristics from both parents
What happens in division 1 in Meiosis?
Firstly the cell goes through the interphase
- chromosomes line up in pairs
- pairs pulled apart
- some of the father’s chromosomes and mother’s chromosomes go into each new cell
- the chromosome number of each new cell is half that of the original cell
What happens in division 2 of meiosis?
Chromosomes line up again
- pulled apart
- you get 4 gametes
What makes stem cells different to normal cells?
Cells in an embryo are all embryonic stem cells
- embryonic cells are unspecialised
- humans have stem cells in places like the bone narrow
What are meristems?
Tissues found in areas of plants which are growing
- unspecialized so can form any cell type in the plant
- form tissues such as phloem and xylem
How can stem cells be used in medicine?
Stem cells can be extracted from embryos and grown to differentiate into different cells.
-stem cells could be used to replace cells which have been damaged.
What are the dangers of stem cells?
Stem cells divide very quickly so a tumour could develop.
Stem cells can contain viruses
What are auxins?
Plant hormones which determine growth at the tips of shoots and roots.
-promotes growth in shoot but inhbits growth in root
What does ‘shoots are positively phototropic’ mean?
They grow towards the light
-when a growth tip is exposed to light, the cells grow faster on that side that’s in the light
What does ‘shoots are negatively gravitropic’ mean?
When a tip is growing sideways, it produces an unequal amount of auxin on the lower side
-the shoots bends in the same direction as gravity
What does ‘roots are positively gravitropic’ mean?
The roots grow in the opposite direction to gravity.
What does ‘roots are negatively phototropic’ mean?
Roots grow away from light.
How do photropism and gravitoprism increase a plant’s chance of survival?
Growing towards the light may allow a plant to absorb more sunlight.
What do Gibberellins do?
Control Germination and flowering
What does ethene do for a plant?
Stimulates shedding of leaves and ripening of fruit.
-ethene is produced by aging leaves -breaks the cells wall causing the leaves to fall off
