Topic 4 Biodiversity and natural resources 4.7 - 4.13 so far Flashcards
name the features of plant cell and their functions compared to an animal cell ?
cell wall, chloroplasts, amyloplasts, vacuole, tonoplast, plasmodesmata, pits, middle lamella. insert picture
Amyloplasts - plant cells that store and make up starch.
tonoplast - molecule that surrounds the vacuole separating vacuole form cytoplasm
plasmodesmata - a narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells and allows communication between them
pits - located on the cell walls of xylem vessels within plant. specifically in the areas where the secondary cell wall is thinner.
Pits in plants are thin areas in cell walls that allow water and nutrients to pass between cells. They also help to transport minerals and food.
what is the role of calcium pectin , lignin and secondary cell wall
secondary cell wall - provide structural and mechanical support it contains cellulose and hemicellulose.
hemicellulose - polysaccharide made up of various sugars including pentose, hexose and ironic acids.
calcium pectin- acts as a glue that holds plant cell wall together by creating cross links between adjacent cells providing structural support. - it is the thing that makes middle lamella sticky.
(calcium is found in the middle lamella combines with pectin to form calcium pectate)
lignin -strength
what is the location and role of specialised Xylem and phloem
located in vascular bundles -
xylem: carries water and dissolves mineral ions form roots to leaves
Phloem: transports biological molecules such as sugars produced by photosynthesis in the leaves
label the cross section of a plant root
insersion of images
What are features of the phloem
Made of living cells called sieve tube elements
these have endplates that contain pores
involved in the movement of dissolved solute
tubes filled with fluid with a minimal cytoplasm
movement of solutes due to translocation
minerals needed for plants ?
nitrates - production of molecules like proteins - enzymes
calcium - vital structural role in providing strong cell wall as forms calcium pectin ( found in middle lamella) which provides rigidity/ strength support to plant.
magnesium - production of chlorophyll - photosynthesis - glucose/ maltose
phosphates -Found in ATP and ADP nucleic acid- active transport
transpiration process
minerals +water
roots - leaves
passive process
adhesion ad cohesion
xylem
translocation process
dissolved sugars
phloem
active transport
loaded and unloaded at source
how does water transport up xylem vessels
due to adhesion water molecules round the sides of xylem due to hydrogen bonds between water and cellulose. cohesion waters dipolar nature flows it to form hydrogen bonds, as water evaporates at leaves particles gain more energy - change state as water molecules move up tugs/ pulls on consecutive water molecule as hydrogen bond breaks. multiplier domino effect.
parenchyma cells in cortex, living cell, used for growth
sclerenchyma cells in vascular bundle, not living, not used for growth, is impregnated with lignin
phloem vessels are living and xylem vessels and non living - lignified
why did William withering extract foxglove to make digitalis soup
to treat dropsy a condition associated with heart failure
practical questions
biodiversity definition
the variety of plant and animal life in the world or in a particular area/ habitat
endemism definition
when a species is only found in a specific geographic area- one place - Endemic species can be plants or animals.
How can biodiversity be measures in a habitat
what is species richness
The number of different species in a given area
genetic diversity meaning
variation of alleles within a species
The variety of genes and genetic traits within a species or population
Hetrezygosity index definition and calculation
heterozygosity index is a measure of genetic diversity within a population, calculated as the proportion of individuals that are heterozygous for a specific gene locus.
species
organisms that are able to breed with each other to produce fertile offspring
with genetic diversity you prefer heterozygous allies because they are two alleles the diversity is increased. the more heterozygous allels you have he more diversity
what cells are live and unlike
describe the process of translocation and transpiration
