3(a) Flashcards
Describe and explain asexual reproduction?(3)
An ordinary cell can make a new cell by dividing in two.
Both new cells are genetically identical to the original cell. This type of division is called Mitosis.
When an organism produces offspring using mitosis this is called asexual reproduction
Describe and explain sexual reproduction?(3)
Sexual reproduction is when genetic information from two organisms is combined to produce offspring which are genetically different to either parent.
At fertilisation a male gamete fuses with a female gamete to form a zygote.
The zygote then undergoes cell division(by mitosis) and develops into an embryo.
State the function of the stamen?(2)
The stamen consists of the anther and filament;
-The anther contains pollen grains that produce the male gametes
-The filament is the stalk that supports the anther
State the function of the carpal?(4)
The carpal consists of the ovary, style and stigma;
-The ovary contains the female gametes inside ovules
-The style is the rod that supports the stigma
-The stigma is the end bit that the pollen grains attach to
What is the difference between pollination and cross pollination?(2)
Pollination is the transfer of pollen from an anther to a stigma so that the male gametes can fertilise the female gametes in sexual reproduction, meanwhile cross-pollination is where pollen is transferred from the anther of one plant to the stigma of another.
How are some plants adapted for insect pollination?(5)
Brightly coloured petals.
Scented flowers and nectaries.
Small sticky pollen grains that stick to insects as they go from plant to plant. Few produced.
Stigma is also sticky to pick up any pollen from other plants by insects.
Small anthers held inside the flower like stigma.
How are some plants adapted for wind pollination?(5)
Small dull petals on the flower.
No nectaries present or scents.
A lot of pollen grains that are light so they can be picked up by wind.
Long filaments that hang anthers outside the flower so that pollen gets blown away in wind.
Large feathery stigma to catch pollen as its carried past. Stigma also hangs outside flower.
Describe and explain fertilisation in a plant?(5)
A pollen grain lands on the stigma of a flower.
Pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule.
A nucleus from the male gamete moves down the tube to join with a female gamete in the ovule.
Fertilisation is when the two nuclei fuse to make a zygote, which forms an embryo.
Each fertilised female gamete is a seed. The ovary develops into a fruit around the seed.
State the conditions required for germination?(3)
Water - to activate the enzymes that break down the food reserves in the seed
Oxygen - for respiration
Temperature - a suitable temperature for the enzymes inside the seed to work
Describe how a germinating seed utilises its food reserves until photosynthesis?(2)
A developed seed contains an embryo and a store of food reserve wrapped in a hard seed coat.
When a seed starts to germinate, it gets glucose for respiration from its own food store. This is the energy it needs to grow.
How can you investigate the condition needed for germination?(4)
Take 4 boiling tubes and put cotton wool at the bottom of each one.
Put 10 seeds on top of the cotton wool in each one.
Set up each tube differently;
Tube 1: water, oxygen, room temp
Tube 2: no water, oxygen, room temp
Tube 3: water, oxygen, low temp
Tube 4: water, no oxygen, room temp
Leave for a few days or so and the only tube to have of germinated will be Tube 1.
Describe and explain how plants reproduce asexually naturally?(3)
Strawberry plants for example send out fast growing stems that grow out sideways called runners.
The runners take root at various points a short distance away and new plants begin to grow.
The new plants are clones of the parent strawberry plant so there is no genetic variation.
Describe and explain how plants reproduce asexually artificially?(2)
Gardeners can take cuttings from parent plants and then plant them to produce clones of the parent plant.
These plants are kept in moist conditions until they are ready to plant.
How is sperm specialised for its function?(3)
Tail-like flagellum that moves through a fluid.
Sac of enzymes to penetrate membrane around egg at the head of the sperm.
Nucleus sits in the mid-piece along with mitochondria to release energy for movement.
How is the male reproductive system adapted for its function?(3)
Scrotum holding testis which has sperm in.
Sperm duct connected to bladder as well as seminal vessel.
Urethra sits next to erectile tissue.
