plant biology ✓ Flashcards
(28 cards)
what happens in photosynthesis ?
light energy is converted into chemical energy
what is the word equation for photosynthesis ?
carbon dioxide + water → glucose + oxygen
what is the symbol symbol equation for photosynthesis ?
6CO2 + 6H2O → C6H12O6 + 6O2
what factors affect the rate of photosynthesis ?
Temperature
Light intensity
Carbon dioxide
what do plants require for growth ?
mineral ions
what ions are needed for chlorophyll ?
magnesium
what ions are needed for amino acids ?
nitrate ions
what is the role of the phloem ?
to transport sucrose and amino acids from the leaves to other parts of the plant
what is the role of the xylem ?
to transport water and mineral ions from the roots to the rest of the pant
what is the origin or carbon dioxide and oxygen ?
waste products of metabolism
where is carbon dioxide and oxygen lost from the plant ?
the stomata of the leaf
how do plants respond to stimuli ?
- negative tropisms the plant grows away from the stimulus
- positive tropisms the plant grows towards the stimulus
what are geotropic responses of roots and stems ?
- roots are positively geotropic they grow towards gravity
- the auxin is on the lower side of the root which means it grows downwards
- stems are negatively geotropic they grow away gravity
- the auxin is on the side closer to the light so it grows upwards
what are phototrophic responses of roots and stems ?
- roots are negatively phototropic
- if the root is exposed to more light the auxin moves to the shaded side
- stems are positively geotropic
what is the role of auxin in the phototropic responses of stems ?
- when the shoot tip is exposed to light it makes more auxin on the side that’s in the shaded than the side that’s in the light
- this makes the cells grow faster on the shaded side so the shoot bends towards the light
what is an experiment to investigate photosynthesis to show the production of oxygen from a water plant ?
- get a light source, ruler, boiling tube attached to clamp stand, capillary tube out of the top of boiling tube with water in and a syringe attached to the capillary tube and a ruler measuring the capillary tube
- add sodium hydrogen carbonate to water to make sure plant has enough CO2
- source of white light placed at specific distance from pondweed
- leave pond weed to photosynthesise
- as it photosynthesises oxygen released will be collected in the capillary tube
- at end of experiment syringe use to draw bubbles of gas in tube along the ruler that is the length of capillary tube
- this is proportional to volume of O2 produced
- repeat experiment with light source placed at different distances from pondweed
what is an experiment to investigate photosynthesis to show the requirements of carbon dioxide in a water plant ?
- get a sealed bell jar and inside put a plant with some soda lime next to the plant with a light above and outside of the bell jar
- soda lime will absorb CO2 out of the air in the jar
- if you leave the plant in the jar for a while and then test the leaf for starch and the leaf will not go blue-black
- shows that no starch has been made in the leaf which means it needs CO2 to photosynthesise
what is an experiment to investigate photosynthesis to show the requirements of light in a water plant ?
- plant that has been grown without light (in cupboard for 48 hours) means that it has used up is starch stores
- cut a leaf from the plant and test for starch
- leaf won’t turn blue-black
- shows that leaf needs light for photosynthesis
what is the difference between sexual and asexual reproduction ?
asexual - one parent the offspring have identical genes to the parent so there’s no variation between the parent and offspring
sexual - involves the fusion of male and female gametes because there are two parents the offspring contains a mixture of their parent’s genes
how are wind pollinated plants adapted for its pollination ?
- small dull petals on flower
- no nectaries or strong scenes
- lots of pollen grain which are small and light
- long filaments that hang the anthers outside the flower so that a lot of pollen gets blown away bu the wind
- large and feathery stigma to catch pollen as its carried past the wind the stigma often hang outside of the flower
how are insect pollinated plants adapted for its pollination ?
- brightly coloured petals to attract the insects
- scented flowers and nectaries to attract insects
- make big sticky pollen grains the grains stick to insects as they go from plant to plant
- stigma is also sticky so that any pollen picked up by insects on other plants will stick to the stigma
what are nectaries ?
glands that secrete nectar
how does fertilisation happen ?
- 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
- nucleus from the male gamete moves down the tube to join with a female gamete in the ovule
- each fertilised female gamete forms a seed the ovary develops into a fruit around the seed
what is fertilisation ?
is when two nuclei fuse together to make a zygote
