cell division: green boxes + forgotten points

Question 1

adaptations of pallisade cells

Answer 1

thin walls to allow diffusion of CO2 .large vacuole to maintain turgor pressure ( hydrostatic pressure)

Question 2

anaphase

Answer 2

centromeres DIVIDE . Chromatids are SEPERATED and pulled to opposite poles by shortening spindle fibres

Question 3

4 types of tissue

Answer 3

NEMC nervous, epilethal, muscle, connective

Question 4

interphase

Answer 4

protein synthesis in G1 energy stores increase + duplicate

Question 5

cartillage tissue

Answer 5

firm and flexible

Question 6

digestive system

Answer 6

slamlors small int, large int, anus, mouth, liver, osophagus, rectum, stomach

Question 7

types of organ systems

Answer 7

digestive system- breaks large insoluble food chunks into small soluble chunks, retians water needed vy body + removes undigestable chunks from body . cardiovascular system - moves blood around body- provide effective transport system gaseous exchange system- brings air into body so that oxygen extracted for respiration and carbon dioxide can be expelled

Question 8

urinary system

Answer 8

buku bladder, ureter, kidney, urethra

Question 9

circulatory system

Answer 9

vahc veins, arteries, heart, capillaries

Question 10

respiratory system

Answer 10

tbbl trachea, bronchi, bronchioles, lungs

Question 11

what happens if stem cells dont divide fast enough or divide too fast

Answer 11

not fast enough- damaged cells cant be replaced quickly too fast=tumours + cancers form !

Question 12

what is mitosis ?

Answer 12

division- results in 2 daughter cells having the same number and kind of chromosomes as parent nucleus

Question 13

source of stem cells

Answer 13

umbilical cords - MULTIPOTENT !

Question 14

diagram of blood cells

Answer 14

Question 15

replacement of red and white blood cells

Answer 15

short life span- needs constant replacement , stem colonies in bone marrow produce 3 million erythrocytes to replace these per day

neutrophils live 6 hours, stem cells produce 1.6 billion per kg per hour . figure increases when infection is present !

Question 16

embryonic stem cells

bone marrow stem cells + umbilical cord

Answer 16

cells present very early on are totipotent. after 7 days, blastocyst forms ( group of cells ) , cells are now in pluripotent state . remain in thi state in fetus until birth

bone marrow cells= multipotent- can be made pluripotent due to growing evidence - advantages of umbilical cord stem cells are that they are in plentiful supply and no invasive surgery is needed. if indivdidual needs needs tissue cultured byt their umbilical cells in the future, body wont reject it !

Question 17

type 1 diabetes

Answer 17

body destroys its own cells !

Question 18

use of stem cells - developmental biology

Answer 18

study of changes that occur as multicellular organisms grow and develop from a single cell - eg fertillised egg and why this might go wrong sometimes

Question 19

prophase (mitosis )

Answer 19

centrioles migrate in pairs to opposite poles

the chromosomes are now tightly coiled and visible as separate bodies under the microscope
the mitotic spindle begins to form at the centrioles

Question 20

stem cell ethics

Answer 20

law in the UK has changed so that embryos can be created in labs for specific stem cells

-embryo has no rights- life begins at conception - disagreement on who wons the genetic material that is being used for research

controversy holds back development of ways to treat different incurable diseases . umbilical stem cells overcome this but they are only multipotent and not pluripotent , thus resrtricting uefulness . adult stem cells cannot divide that well and could qquire mutations .

research is ongoing on how to turn tissue stem cells into pluripotent stem cells - induced pluripotent adult stem cells (ipsc)

use of plant stem cells dont raise that many ethical concerns

Question 21

green box: scid

Answer 21

severe combined immuno- defficiency

produces no T cells and without T eclls, B cells dont function either . normally treated w bone marrow transplat - cells differentiate into healthy wbc

aim: remove bone marrow from patients body and gentically modify them so the yfnction properly and produce WBC needed. these are put back into the patient should the condition be corrected

ethical concerns: some childrne developed leukemia - still has potential in the future though

Question 22

green box: plant cells

Answer 22

leads to unlimited, cheap supply of drugs from plants to be used in medicine

paclitaxel- sued to treat breast cancer - obtained from bark of yew trees- trees have to be mature thus supply is limiteda nd extraction process is difficult and expensive

alternative ways- still difficult and expensive