plant hormones Flashcards
why do plants produce hormones?
to coordinate and control growth and responses to light (phototropism) and gravity (gravitropism/geotropism)
give 1 example of a plant hormone
auxin
what can unequal distributions of auxin cause?
unequal growth rates in plant roots and shoots
what are auxins used for in agriculture and horticulture?
weed killers
rooting powders
promoting growth in tissue culture
what is ethane used for in agriculture and horticulture?
used in the food industry to control ripening of fruit during storage and transport
what are gibberellins used for in agriculture and horticulture?
can be used to end seed dormancy, promote flowering and increase fruit size
sexual reproduction unveiled the j___ /fusion of male and female g___
joining
gametes
what is the male gamete in animals? female?
male: sperm
female: egg cells
what is the male gamete in flowering plants? female?
male: pollen
female: egg cells
what leads to a variety in offspring?
a mixing of genetic information
what process produces gametes?
meiosis
what type of reproduction only involves 1 parent?
asexual
cells in ovaries and testes divide by ___ to form ___
meiosis
gametes
what are the 3 stages of when a cell divides to form gametes (meiosis)?
copies of genetic information are made
the cell divides twice to form four gametes
all gametes are genetically different from each other
gametes join at ___ to restore the normal number of ___
fertilisation
chromosomes
the new cell divides by ___ to form an ___. as the ___ develops the cells ___
mitosis
embryo
embryo
differentiate
give 2 advantages of sexual reproduction
produces variation in the offspring
of the environment changes variation gives the organism an advantage by natural selection
give 4 advantages of asexual reproduction
only 1 parent needed
more time and energy efficient as do not need to find a mate
faster than sexual reproduction
many identical offspring can be produced when conditions are favourable
which 3 organisms reproduce by both methods? explain for each
malarial parasites reproduce asexually in the human host, but sexually in the mosquito
many fungi reproduce asexually by spores but also reproduce sexually to give variation
many plants produce seeds sexually, but also reproduce asexually (eg. strawberry plants by runners or bulb division such as daffodils)
