sustainability and plant materials

Question 1

sustainability

Answer 1

using resources in a way that requirements of current generation are met without depleting these resources for future generations
requires renewable resources, can be replenished within a short time frame to sustain rate of consumption

Question 2

whatre sustainable practices

Answer 2

minimise damage done to the environment and it’s resources, resources left for future generations

e.g replanting trees after logging

Question 3

whyre unsustainable practices limited

Answer 3

finite supply of resources

Question 4

why is using plant fibres more sustainable than oil-based products

Answer 4

-fewer fossil fuels are used and plants can be replanted for next gen
-plants are biodegradable (can be broken down by living organisms into harmless substances)
-extracting and processing oil are expensive and difficult procedures
-but ropes from plant fibres are typically not as strong as plastic ones

Question 5

starch and sustainable practices

Answer 5

-plants store excess starch in their cells
-starch can be used to make bioplastics which are more more sustainable than oil-based plastics as the plants theyre obtained from can be replanted for next generation
but not all bioplastics are biodegradable
-starch can be used to make bioethanol, can be used to fuel vehicles
-using starch to make biofuels is more sustainable than using oil

but using biofuels is often carbon neutral not negative as carbon absorbed by growing plant is released back into atmosphere when burned

Question 6

independent assortment:

Answer 6

-homologous chromosomes, paternal and maternal pair up randomly
-which one ends up ontop of the other is random
-pulled towards the equator
-pulled apart & chromosomes in each daughter cell will be random
-during meiosis 1

Question 7

does mitosis occur in gametes

Answer 7

no

Question 8

does the diploid parent cell at the beginning of meiosis have paternal and maternal dna

Answer 8

yes

Question 9

meiosis 1

Answer 9

diploid cell
cell contents replicate
2 cells with 1 chromosome
but double to number of chromatids
so half the number of chromosomes in each cell but double the number of chromatids
after meiosis 2 there are the same number of chromosomes in each cell as after meiosis 1 but half the number of chromatids

diploid cell (46 chromosomes, 46 chromatids)-replicated so diploid cell with double number of chromatids but same number of chromosomes (46 chromosomes, 92 chromatids)
now meiosis begins
crossing over occurs
then cell divides into 2 cells with half the number of chromosomes as origional and replicated cell but same number of chromatids as origional cell and half the number of chromatids as replicated cell
meiosis 2 these 2 daughter cells divide to produce 4 granddaughter cell with 23 chromosomes and 23 chromatids
half number of chromosomes and chromatids as
2n-2n-n
says half number of chromosomes as chromosomes are replicated before meiosis

Question 10

meiosis 2

Answer 10

n-1/2n with 2 cells produced in meiosis 1
chromatids that

Question 11

how many chromosomes do 2 sister chromatids make up

Answer 11

1

Question 12

does the chromosome number half during meiosis 1 or 2?

Answer 12

1

Question 13

sets of chromosomes in cells at each stage of meiosis including replication

Answer 13

origional cell=2 sets of chromosomes
cell with replicated genetic info=2 sets of chromosomes
daughter cells=1 set of chromosomes
granddaughter cells=1 set of chromosomes

Question 14

during meiosis 1 what is split to form 2 haploid nuclei in 2 cells

Answer 14

homologous pairs (1 paternal, 1 maternal, containing the same genes in same order but with diff alleles

Question 15

how many homologous pairs are contained within 1 SET of chromosomes

Answer 15

2

each pair consists of 1 maternal chromosome and one paternal chromosome

Question 16

what happens during meiosis 2

Answer 16

the chromatids that make up each chromosome separate to produce 4 haploid nuclei

Question 17

how many chromatids does each chromosome in each cell consist of at the end of meiosis 2

Answer 17

1 chromatid

Question 18

stages of mitosis in order

Answer 18

interphase- replicaysh
prophase
metaphase
anaphase
telophase

PMAT

Question 19

why arent chromosomes visible before prophase

Answer 19

dna loosely coiled in chromatin

when condensed becomes visible

Question 20

what is a centrosome

Answer 20

contain centrioles, centrioles organise & produce spindle fibres
consist of 2 centrioles

Question 21

prophase

Answer 21

-chromosomes condense
-chromosomes now visible when stained
-chromosomes contain 2 sister chromatids, each containing one DNA molecule and joined at the centromere
-centrosomes move to opposite poles of the NUCLEUS
-spindle fibres begin to emerge from the centrosomes
-nuclear envelope breaks down into small vesicles

Question 22

metaphase

Answer 22

chromosomes line up at the equator of the SPINDLE
spindle fibres attach to centromeres
each sister chromatid is attached to a spindle fibre from opposite poles

Question 23

anaphase

Answer 23

sister chromatids separate at the centromere
spindle fibres begin to shorten
separated sister chromatids (NOW CALLED CHROMOSOMES)
pulled to opposite poles by spindle fibres

Question 24

telophase

Answer 24

chromosomes arrive at opposite poles and
nuclear envelopes begin to reform around each set of chromosomes
spindle fibres break down

Question 25

interphase

Answer 25

includes G1, S and G2 G1: production of ribosomes, RNA and proteins needed for growth at some point during G1 cell receives signal to divide again signals S phase: replication of DNA in the nucleus S stands for synthesis G2:newly synthesised DNA is checked and any errors are usually repaired other preparations for cell division are made like production of tubulin protein which is used to make microtubules for the mitotic spindle (the mitotic spindle is made of spindle fibres) before mitosis cell contains 92 dna molecules as chromosomes have been replicated mitosis and meiosis are division not replication

Question 26

cytokinesis

Answer 26

cell division follows M phase (mitosis) once the nucleus has divided into 2 identical nuclei the whole cell divides and one nucleus moves into each cell to create 2 genetically identical daughter cells -constriction of cytoplasm between the 2 nuclei (in plant cells a new cell wall is formed)

Question 27

what is movement from one stage of the cell cycle to another triggered by

Answer 27

chemical signals called cyclins

Question 28

in which phase does cell growth stop?

Answer 28

mitosis

Question 29

explain how differential gene expression allows cells to become specialised

Answer 29

a stimulus can cause different proteins to be synthesised by a cell

Question 30

advantages of using plant resources

Answer 30

more sustainable as plants can be grown, oils are a finite resource plants take in carbon dioxide from the atmosphere during photosynthesis can be less expensive as production and extraction of oils is expensive -land unsuitable for agriculture can be used for growing plant resources -less plastic produced so less contributing to landfills -burning biofuels carbon neutral, no net carbon released

Question 31

disadvantages of using plant resources

Answer 31

can contribute to deforestation regrown plants may reduce biodiversity if only a few species are planted -land used for growing plant resources are replacing rainforests and agricultural land -loss of wildlife habitats -current uncultivated land may be unsuitable any carbon taken in from the atmosphere by plants used for biofuels will be released back into the atmosphere once theyre burned ropes made of plant fibres often have a lower tensile strength than those made of oil based plastics -fossil fuels used in manufacturing and transport -lower quality products often -

Question 32

why wouldnt biofuels grown from sugar cane in brazil be used in the uk

Answer 32

-sugar cane may not grow in the uk -no land space to grow equivalent area of plants -bioethanol would have to be imported which is expensive and not carbon neutral -cars would have to be modified

Question 33

advantages of plant fibres

Answer 33

-high in tensile strength -waterproof (xylem and sclerenchyma lignified) -sustainable