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BIO HL > B2.3 Cell Specialisation > Flashcards

B2.3 Cell Specialisation Flashcards

(60 cards)

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1
Q

What are stem cells

A

cells that continue to grow and divide repeatedly, rather than specialise

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2
Q

What are morphogens

A

a small number of genes determine body patterns during the embryo development
They are extracellular and occur across a gradient of concentrations

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3
Q

what do morphogens do

A

high concentration of morphogens will cause cells to act diff from when there is a low concentration
this means initiation/inhibition of gene expression is a result of different concentrations of morphogens
they control the way cells differentiate and develop in specific tissues

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4
Q

what is a blastocyst

A

a tiny balls of cells, formed through continual cell division

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5
Q

what are embryonic stem cells

A

cells found on the inner cell mass of the blastocyst

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6
Q

What are adult stem cells

A

few cells that keep many of the properties of embryonic stem cells

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7
Q

what does it mean that stems cells are self renewing and have potency

A

they maintain undifferentiated states and have the capacity to differentiate in mature cell types

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8
Q

what is a stem cell niche

A

an area of tissue that provides a specific environment where stem cells exist in undifferentiated and self renewable states
They can then receive stimuli to determine their behavior

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9
Q

What can a result of signals in stem cell niches be

A

maintenance of a dormant state
cause to self renew
commit to a more differentiated state

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10
Q

Bone marrow is ..

A

the site of blood cell formation for most vertebrates

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11
Q

what is an osteoblast

A

cells which regulate the creation of bones

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12
Q

what is Hematopoietic Stem Cells

A

they produce RBC, WBC and platelets
They are closely connected with osteoblasts because they rely on each other to function

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13
Q

What is the vascular niche

A

in the adult bone marrow, is a place for stem cell mobilisation , proliferation , differentiation

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14
Q

What are hair follicles

A

they are structures that can regenerate in order to continuously produce new hair
They are multipotent and have the potential to increase rapidly

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15
Q

what happens during the growth phase of hair follicle stem cells

A

becomes activated to regenerate the hair follicle causing hair to grow longer every day

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16
Q

what happens to hair during the resting phase of hair follicles

A

the stem cells are dominant and hairs shed more easily

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17
Q

what causes hair to turn white

A

hair follicles have pigment cells that make melanin
certain stem cells act as pigment producing.
Fewer of these cells become active and hair loses its ability to produce melanin

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18
Q

what can lead to hair loss with age

A

imbalance in stem cells differentiation and altered stem cell activity

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19
Q

What are totipotent stem cells

A

the most versatile type, they are the first formed stem cells of a zygote
Can become any type, including cells that make the placenta

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20
Q

what are pluripotent stem cells

A

slightly limited in potential, can give rise to any cell type that makes up the body, but cannot make placental or totipotent stem cells

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21
Q

when are pluripotent stem cells found

A

as blastocyst is formed, stem cells in subsequent division are pluripotent

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22
Q
A
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23
Q

what is multipotent stem cells

A

stem cells are only able to develop and form the nervous system after differentiation has occurred
can develop into diff cell types but very limited
have limited capacity for self renewal

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24
Q

what is the function of multipotent stem cells

A

they can create, maintain and repair the cells of one particular organ or tissue

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25
why are egg cells large
the large body allows it to store nutrients for the early development of the fertilised egg
26
why are sperms tiny
they only need to hold the nucleus for delivery
27
purpose of the sperms long flagellum
provides propulsion to reach the egg
28
shape and size of RBC related to it's function
much smaller than WBC so they can fit through small lumen of capillaries have large SA compared to volume , allowing oxygen to diffuse at a faster rate
29
what does WBC do
attack and destroy foreign matter large size allows them to engulf pathogens or produce antibodies
30
why are neurons and nerve cells long
allow electrical impulses to be sent without interruption over a long distance allows fast transmission
31
what are striated muscle fibres
multinucleated cells attach to muscles to allow movement. their length allows them to coordinate contraction and has an effect on muscle force generation
32
what factors the rate at which materials can enter or leave the cell
the surface area
33
what happens to SA and volume as cells increase in size
volume increases faster than the surface area, SA to volume ratio falls means less and less cytoplasm has access to SA for exchange of materials
34
what does low SA to volume ratio show in cells
cells cannot constantly grow larger When limit is reached, the cell may then divide
35
what are adaptations of RBC to increase SA to volume ratio
they have biconcave shape flattened to increase SA and diffusion no nucleus shape of cell increases its flexibility
36
what are adaptations of Proximal convoluted tubule to increase SA to volume ratio
walls of tubule are one cell thick and packed with mitochondria inside surface folded into microvilli, forming brush border ( increase SA) on other side, invaginations formed to increase surface area
37
What is Proximal convoluted tubule
the longest section of the nephron, reabsorbs large amounts of the filtrate
38
what is an adaptation of an alveolus to maximise gas exchange
wall is one cell thick, right next to capillaries
39
what are features of Type 1 pneuomocytes
involved in gas exchange between the alveoli and the capillaries have flattened shape, extremely thin cells tightly connected to prevent leakage of tissue fluid into alveolar air space
40
what are features of type 2 pneumocytes
they produce detergent like mixture of lipoproteins and phospholipids known as surfactant which line inner surface of alveoli cuboidal and big contain many secretory vesicles surfactant lowers surface tension so walls dont collapse inwards of alveoli
41
what are macrophages
they are abundant in the surface film and protect the delicate structure of the alveoli originate bone marrow stem cells and disperse in the body through blood circulation they migrate into alveoli where phagocytes ingest foreign stuff
42
what does myogenic origin mean
when the impulse to contract is generated by the muscle ( found in heart)
43
what is the structure of heart muscle cells
each cell has a tubular structure composed of chains of fibres each fibre composed of a mass of myofibrils
44
what does cardiac muscle consists of
cylindrical branching columns of fibres, allowing for 3d contraction and signal to spread quickly
45
in cardiac muscle, what is structure of the fiber it is composed of
each fibre has a single nucleus and they have a striated appearance they are surrounded by a plasma membrane known as the sarcolemma, well supplied with mitochondria and capillaries
46
what does the structure of cardiac muscle cells allow
propagation of stimuli through the heart wall
47
what is present at the junction between cardiac muscle cells
intercalated discs, helps synchronise contraction of the muscle
48
what does an intercalated disc consist of
double membrane with gap junctions, through which there are cytoplasmic connections between adjacent cardiac cells
49
what do gap junction in cardiac muscle cells allow
continuous flow of cytoplasm between cells
50
what does the branching structure of the cardiac muscle allow
connection to multiple cells and provides a large SA of contact between cells, allowing them to work together and synchronize activity
51
why is network system of atria completely separate from ventricles
to ensure a transmission delay of electrical signal
52
what are skeletal muscles
they attach the moveable parts of skeletons, contractions of these muscles bring about movements. Muscles are attached by tendons and work in antagonistic pairs
53
what do skeletal muscles consist of
bundles of muscle fibers, each of which consists of mass of myofibrils
54
what do skeletal muscle fibres consist of
they appear striped so known as striated each fibre consists of parallel myofibrils, within a sarcolemma they are multinucleated and contain specialised ER Sarcolemma folds to form a sarcoplasmic reticulum, network around individual myofibrils
55
what are similarities between skeletal muscle and cardiac mucle
both surrounded and enclosed by sarcolemma from which transverse tubules are present Sarcoplasmic reticulum present in both both striated and similar arrangement of actin and myosin filaments muscle fibres can shorten many mitochondria to increase ATP for contraction
56
what is the advantage of delaying the two divisions of meiosis in egg cells
they're provided with genetic material for longer, for mRNA production and protein synthesis,
57
what is the function of follicle cells in egg cell
nourish and protect cell
58
function of jelly coat/zona pellucida in egg
binding of sperm cells prevents polyspermy and premature implantation
59
function of cortical granules in egg
prevents polyspermy
60
function of plasma membrane in egg cell
surrounds nucleus and contains microvilli for absorption of nutrients

BIO HL (23 decks)

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