Variation & Plants - Unit 2 Flashcards
What is the definition of variation ?
Differences that occur between individual members of a species called variation
What is the type of inheritance for discrete variation?
Single gene (where measurements fall in to distinct groups)
What is the type of inheritance for continuous variation?
Polygenic (range of values)
What do genes do?
code for proteins
What are Alleles
Different forms of the same gene
What types of alleles always show up in the appearance of organism and what alleles don’t?
Dominant (RR) , Recessive (rr)
What is a genotype?
The alleles an organism carriers for a particular characteristic
What does it mean if an organism is homozygous?
The alleles are the same
What is a phenotype?
The physical features of a characteristic
What does it mean if an organism is heterozygous?
The alleles are different
How come some predicted ratios are not correct?
Fertilisation is a random process that contains an element of choice
What are the plants transport organs?
Leaves, stem, roots
what is the structure of a leaf
Waxy Cuticle ,Upper Epidermis,Palisade mesophyll ,Spongy mesophyll ,Lower epidermis ,Guard cells ,Stomata
What are the structural features and function of the xylem?
Dead, Lignin rings. Once water is absorbed its carried upwards by the xylem towards leaves for photosynthesis
What are the structural features and function of the phloem
Alive, next to xylem tissue. Carries sugars around the plant up and down
What is transpiration? (short)
the evaporation of water into the atmosphere from leaves of plants
What is transpiration? (long)
Water moves from the roots of a plant to the leaves
Water is vital for the transport of minerals within a plant and for photosynthesis
Water is lost through the stomata on the underside of the leaf
Root hair cells increase surface area for the absorption of water
Water moves into root hair cells by mitosis
Water moves through stem and leaves through xylem
Water exits through stomata in leaves
How can you measure the rate of transpiration?
Bubble potometre
What are 4 things that increase the rate of transpiration?
increase in temp, increase in wind speed, increase in surface area, decrease in humidity
