Cell Division and Specialisation

Question 1

what functions are needed for any organism to stay alive

Answer 1

support/structure
exchange (with environment)
digestion
respiration
reproduction

Question 2

cell

Answer 2

smallest functional unit of living matter

Question 3

tissue

Answer 3

group of cells with similar structure and similar function

Question 4

organ

Answer 4

group of tissues working together with a specific function

Question 5

organ system

Answer 5

group of organs working together with a specific function

Question 6

organism

Answer 6

group of organ systems that perform all functions necessary to stay alive

Question 7

egs of cell -> tissue -> organ -> organ system

Answer 7

Question 8

specialised

Answer 8

having different adaptations to help carry out specific function

Question 9

nerve cell (what is point of axon, synapses?)

Answer 9

Question 10

what are muscle cells? (skeletal and smooth)

Answer 10

Question 11

striated muscle cells diagram, what are their 3 adaptations?

Answer 11

Question 12

sperm cells

Answer 12

Question 13

root hair cells

Answer 13

absorb water and mineral ions from soil
underground so no chloroplast

Question 14

photosynthetic cells

Answer 14

= palisade cell, long and thin so lots can fit into top layer of leaf

Question 15

xylem cells

Answer 15

xylem is a transport tissue in plants that carries water and mineral ions from roots to highest leaves (made up of xylem cells)
UNIDIRECTIONAL TRAVEL
cells are dead?

Question 16

phloem cells

Answer 16

Question 17

mitosis (membrane?)

Answer 17

DNA in chromosomes copies itself ready for mitosis. most time is spent in this phase (interphase)

The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears (prophase)

Chromosomes and their copies line up in the middle of the cell (metaphase)

Chromosomes and their copies are pulled to different ends of the cell - ONE SET TO E4ACH SIDE (anaphase)

New membranes form around the chromosomes at each end of the cell (telophase)

The cell membrane pinches in and eventually divides into two daughter cells (cytokinesis)

Question 18

cell cycle

Answer 18

interphase (DNA replication and growth) - cell gets ready to divide, cell grows, DNA duplicates, more organelles made

mitosis - genetic material separates, SET OF CHROMOSOMES GET PULLED TO EACH SIDE and cell gets ready to divide into 2 daughter cells

cytokinesis (cell division) - cytoplasm and cell membrane split, (2 new daughter cells are made)

Question 19

cells divide for:

Answer 19

growth (hair, nails)
development (embryos, muscles)
replacement (skin, blood cells)

Question 20

normal cell division

Answer 20

regulated by genes - ensure cells only divide when needed, then stop

apoptosis: body can destroy cells that are old/damaged (controlled cell death)

Question 21

tumour

Answer 21

(caused by mutation) cells growing abnormally and uncontrolled

Question 22

benign vs malignant tumours

Answer 22

Question 23

metastases

Answer 23

secondary tumours

Question 24

causes of cancer

Answer 24

lifestyle:
smoking
obesity (bowel)

viruses:
HPY (cervical)

genetics:
faulty BRCA gene (high risk of breast cancer)

carcinogens:
asbestos (lung)
alcohol (liver)
UV exposure (skin)

Question 25

stem cell

Answer 25

undifferentiated cell that has the potential to become any type of cell needed

Question 26

what happens during first few days after fertilisation

Answer 26

stem cells divide

Question 27

differentiation (and eg)

Answer 27

cells developing structural differences enabling them to carry out a specific function eg cytoplasm and cell membrane elongate making connections over large distances, forming a nerve cell

Question 28

differentiation in animals vs plants

Answer 28

plant can keep differentiating throughout their life differentiation is reversible in plants

Question 29

how can stem cells differentiate into any cell

Answer 29

they have access to all genes

Question 30

adult / somatic stem cells? why are they needed? are they easy to find?

Answer 30

tissue-specific / multi potent stem cells - they can only differentiate into one type of tissue (with limited types of cells) - hard to find! eg bone marrow because not all cells can undergo mitosis (eg RBCs, skin cells)

Question 31

bone marrow

Answer 31

soft inner tissue of bones where blood cells are formed rapidly divide and differentiate to form a variety of cells can only create blood cells (RBCs, WBCs, platelets)

Question 32

plant differentiation

Answer 32

- differentiate throughout their life - undifferentiated cells form at meristems (roots and shoots) where mitosis is almost continuous - cell don’t differentiate until they are at their final position in the plant - not permanent- cells can revert back, relocate and respecialise

Question 33

therapeutic cloning

Answer 33

a way of producing stem cells with the same genetic makeup as the patient

Question 34

why are embryonic stem cells useful (egs)

Answer 34

dysfunctional/damaged cells that can’t repair themselves cause health problems: - pancreatic cells -> type 1 diabetes - spinal cord neurones -> paralysis - cardiac muscle fibres after heart attack - brain neurones -> Alzheimer’s disease

Question 35

why is therapeutic cloning useful (what are the alternatives)

Answer 35

although stem cells can be taken from early developing embryos and stimulated to grow into specific body cells there is a risk of rejection if coming from a donated embryo - lifelong need for immunosuppressants there would be fewer problems if it came from a family member or from donor with closely matched tissue types

Question 36

phloem vs xylem

Answer 36

phloem carries bidirectional the products from photosynthesis xylem carries unidirectional water and mineral ions xylem cells are lignified, phloem not but have companion cells

Question 37

issue with stem cells (dont need to know all)

Answer 37

Clinical issues * no guarantee of how successful these therapies will be, eg use of stem cells in healing damage caused by Parkinson's disease * difficult to find suitable stem cell donors * difficult to obtain and store a patient's embryonic stem cells * mutations have been observed in stem cells cultured for a number of generations - some mutated stem cells have been observed to behave like cancer cells. * cultured stem cells could be contaminated with viruses which would be transferred to a patient Ethical issues * a source of embryonic stem cell is unused embryos produced by in vitro fertilisation * for therapeutic cloning, is it right to create embryos for therapy, and destroy them in the process? * embryos could come to be viewed as a commodity, and not as an embryo that could develop into a person. * at what stage of its development should an embryo be regarded as, and treated as, a person? Social issues * educating the public about what stem cells can, and can't do, is important * do the benefits of stem cell research and use outweigh the objections? * much of the research is being carried out by commercial clinics, so reported successes are not subject to peer review * patients could be exploited - paying for expensive treatments and being given false hope of a cure when stem cell therapies are only in their developmental stages

Question 38

prokaryotic vs eukaryotic cells | SIZE, outer layers, contents, genetic material, cell division

Answer 38

Question 39

ribosomes

Answer 39

do protein synthesis

Question 40

chromosome

Answer 40

structure within the nucleus of a cell that carries genetic information in the form of DNA