1.1 cell biology

Question 1

cell theory states that

Answer 1

1. all living organisms are made of one or more cells
2. the cell is the basic unit of structure and organization in organisms
3. all cells come from other cells

Question 2

what are 3 exceptions to cell theory?

Answer 2

Striated muscle fibres, Aseptate fungal hyphae, and giant algae

Question 3

why are striated muscle fibers an exception to cell theory?

Answer 3

• Muscle cells fuse to form very long fibres (>300mm)
• multi-nucleated
• Challenges the idea that cells always function as autonomous units

Question 4

why is Aseptate fungal hyphae an exception to cell theory?

Answer 4

• continuous cytoplasm
• challenges the idea that cells are individual units

Question 5

why is giant algae an exception to cell theory?

Answer 5

• giant, grow up to 100mm in length w only 1 nucleus
• challenges the idea that larger organisms are always made of many microscopic cells

Question 6

acronym for functions of life

Answer 6

mr h gren

Question 7

functions of life

Answer 7

metabolism
response
homeostasis
growth
reproduction
excretion
nutrition

Question 8

metabolism

Answer 8

all the enzyme-catalyzed reactions in the cell or organism. this includes respiration

Question 9

response

Answer 9

the ability to respond to and interact with the environment

Question 10

homeostasis

Answer 10

the maintenance and regulation of internal cell conditions

Question 11

growth

Answer 11

changing size/shape

Question 12

reproduction

Answer 12

producing offspring by sexual or asexual reproduction

Question 13

excretion

Answer 13

the removal of metabolic waste

Question 14

nutrition

Answer 14

obtaining organic molecules via absorption (eg feeding) or synthesis (eg photosynthesis)

Question 15

heterotroph

Answer 15

an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter (consumers, not producers)

Question 16

functions of life in paramecium

Answer 16

M - metabolic reactions mostly in cytoplasm, respiration in mitochondria
R - cilia feel particles in the surrounding environment
H - contractile vacuole regulate water content by expelling water from the cell membrane
G - gain biomass
R - cell division (mitosis)
E - the cell membrane regulates excretion. vesicles release materials (exocytosis)
N - the cell membrane surrounds food and takes it into the cell (endocytosis)

Question 17

paramecium

Answer 17

genus of unicellular heterotroph protozoans

Question 18

chlorella

Answer 18

photosynthetic unicellular organism

Question 19

functions of life in chlorella

Answer 19

M - metabolic reactions in cytoplasm, photosynthesis in chloroplast, respiration in mitochondria
R - adapts to light and concentrations of solutes in environment
H - large central vacuole to store and regulate water content
G - gain biomass
R- mitosis
E - cell membrane regulates transport out of the cell (ex: exocytosis)
N - photosynthesis produces organic carbon compounds (biomass)

Question 20

why is sa:vol ratio important in the limitation of cell size?

Answer 20

• more surface area means more surfaces for transport across the membrane
• less volume means particles can move thru-out the cell in a shorter time
• small cells tend to have a large sa:vol ratio
• transport (ex: diffusion) is more efficient when a cell has a high sa:vol ratio

Question 21

structure of multicellular organisms

Answer 21

atoms → molecules → cells → tissues → organs → organ systems → multicellular organism

Question 22

why are multicellular organisms’ cells differentiated?

Answer 22

to carry out diff functions

Question 23

examples of differentiated cells

Answer 23

red blood cells, nerve cells, female reproductive/egg cell, male reproductive/sperm cell

Question 24

function & special features of red blood cells

Answer 24

function: to carry oxygen
features:
* large sa for oxygen to pass thru
* contains haemoglobin, which joins w oxygen
* no nucleus

Question 25

function & special features of nerve cells

Answer 25

function: to carry nerve impulses to diff parts of the body features: * long * connections at each end * can carry electrical signals

Question 26

function & special features of egg cells

Answer 26

function: to join w male cell, and then to provide food for the new cell that's been formed features: * large * contains lots of cytoplasm

Question 27

function & special features of sperm cells

Answer 27

function: to reach female cell, and join it features: * long tail for swimming * head for getting into female cell

Question 28

how to cells become different?

Answer 28

* not all genes are activated in all cells * only some genes are expressed. ex: the set of genes expressed in a skin cell will differ from the genes expressed in a red blood cell

Question 29

stem cells

Answer 29

unspecialized cells that continuously divide and specialize into diff cells

Question 30

3 types of stem cells

Answer 30

totipotent, pluripotent, multipotent

Question 31

totipotent stem cells

Answer 31

can form any cell type, as well as extra-embryonic (placental) tissue (e.g. zygote)

Question 32

pluripotent stem cells

Answer 32

can form any cell type (e.g. embryonic stem cells)

Question 33

multipotent stem cells

Answer 33

can differentiate into a number of closely related cell types (e.g. haematopoeitic adult stem cells)

Question 34

unipotent stem cells

Answer 34

can not differentiate, but are capable of self renewal (e.g. progenitor cells, muscle stem cells)

Question 35

potential uses of stem cells

Answer 35

* replacing/repairing damaged tissues, particularly nervous tissue, heart tissue and blood cells in leukemia patients * treatment of diseases such as Parkinson's and diabetes * testing effects of toxins or drugs on various tissues * testing gene therapy techniques * growing new organs

Question 36

why is the use of embryonic stem cells controversial?

Answer 36

it results in the destruction of the embryo which may be considered a living organism

Question 37

induced pluripotent stem cells (iPSC)

Answer 37

the turning of adult cells into stem cells via nuclear transfer

Question 38

Stargardt's macular dystrophy

Answer 38

* an inherited disease that results in the eventual loss of vision in young people * a mutation in the gene causes a transport protein to malfunction in retinal photoreceptors (light sensitive cells)

Question 39

use of stem cells to treat Stargardt's macular dystrophy

Answer 39

* recent clinical trials have used embryonic stem cells to create retinal cells that are injected in the retina. these cells attach to the retina, become functional, and improve vision * still undergoing clinical trials

Question 40

leukemia

Answer 40

originates in the bone marrow. production of a high number of abnormal leukocytes (white blood cells). risk factors include ionizing radiation, chemicals (benzene), chemotherapy

Question 41

what stem cells are used in the treatment of leukemia?

Answer 41

multipotent (adult) hematopoietic stem cells from a bone marrow donor, who needs to have the same antigens on their leukocytes as the host

Question 42

how do the stem cells function in the treatment of leukemia?

Answer 42

1. recipient's immune system is destroyed (radiation or chemotherapy) 2. stem cells are transplanted into the bone marrow and proliferate 3. after a few weeks blood cell counts normalize and the immune system regenerates

Question 43

benefit + risks of using stem cells to treat leukemia

Answer 43

benefit: a chance to cure or provide long-term remission, with increasing survival rates risk to donor: drug interactions, pain from procedure risk to recipient: can lead to death from infection (before or after transplant), or rejection of host cells

Question 44

typical size of bacteria

Answer 44

1 micrometer

Question 45

typical size of plant/animal cell

Answer 45

100 micrometers

Question 46

typical size of virul

Answer 46

100nm