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BIOLOGY -MODULE 2 > Stem cells and differeniation > Flashcards

Stem cells and differeniation Flashcards

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1
Q

Enthrocytes

A

Flattened biconcave shape - increases SA:V ratio, maximising the oxygen absorption - quicK diffusion rate

No nuclei - more space for haemoglobin

Flexible - to fit through narrow capillaries

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2
Q

Neutrophils

A

Part of immune response

Multi lobed nucleus- for squeezing through small gaps to get to site of infection

Granular cytoplasm - Contains lysosomes that conrain enzymes used to attack pathogens

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3
Q

Sperm cell

A

Male gamete
Tail/ flagellum - capable of movement

Lots of mitachondria/ enzymes - supply energy to swim

Acrosome on head- digestive enzymes are released to digest protective layers around the ovum and allow spleen to penetrate - fertilisation

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4
Q

palisade

A

Found in mesophyll

  • chloroplasts ABSORB large amounts for photosytnethsis
  • cells CLOSELY slacked to form a continuous layer

THIN walls increase diffusion rate of CO2

Large vacuole to maintain turgor pressure

Chloroplasts move within cytoplasm in order to absorb more light

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5
Q

Root hair cells

A

Surfaces of roots near growing tips

  • long hair liek extensions called Root hair cells which I crease the surface area of cell

This MAXIMISES uptake

Lots of mitachondria which provide more energy for active transport

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6
Q

GUARD cells

A

Form small opening called stomata

Needed for co2 to enter plants for photosynthesis

Loosing h20 causes them to become LESS swollen as a result of osmotic forces - change shape and stoma closes to prevent further loss

Cell wall - thicker on ONE side

Cell doesn’t change shape symmetrically as it’s volume changes

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7
Q

What is a tissue

A

A tissue is made of a collection of diffferentiated cells that have a specialised function/s

As a result each tissue is adapted for a particular function within the organism

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8
Q

4 main categories of tissues in animals

A

Nervous tissue
Epithelial tissue
Muscle tissue
Connective tissue

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9
Q

Nervous tissue

A

Adapted to support the transmission of electrical impulses

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10
Q

Epithelial tissue

A

Adapted to cover body surfaces, internal and external

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11
Q

Muscle tissue

A

Adapted to contract

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12
Q

Connective tissue

A

Adapted to either to hold other tissue together as as a transport system

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13
Q

Squamous epithelium

A

Made up of specialised squamous epithelial cells, sometimes lnown as a PAVEMENT epithelial due to flat appearance

Very THIN due to squat/ cells that make it up and only one cell thick

Present when rapid diffusion across a surface is essential

Forms lining of lungs and allows RAPID diffusion of oxygen into the blood

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14
Q

Ciliated epithelium

A

Made up of ciliated epithelial cells
Hair like structure called CILIA on one side - move in RHYMIC manner
Lines tranchea causes mucus to be swept away by the lungs
Goblet cells RELEASE mucus to trap unwanted particles present in the air , preventing particles which may be bacteria from reaching alveoli once inside the lungs
Microtubules - 9+2 arrangement
Fallopian tubes
Mobile or stationary e.g. sensory organs

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15
Q

Muscle

A

Needs to be able to contact in order to move bones which In turn move the different part of the body

Different types of muscle fibres

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16
Q

Smooth muscle

A

Inability to control their movement

HOLLOW organ e.g. uterus and stomach

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17
Q

Skeletal muscle

A

Attach to bones and have the main function of contracting to facilitate movement of our skeleton

Contain microtubules which contain contractile proteins

18
Q

Cardiac muscle

A

High contractile strength

SOLELY in the walls of the heart

Similarities to skeletal muscles in that is stimulated and smooth muscles in that is contraction are NOT under contious control

19
Q

Epidermis

A

Single layer of closely packed cells covering surfaces of plants

Covered by wa y cuticle( waterproof)to prevent loss of water

Stomata- formed by a pair of guard cells that open and close

Allow CO2, O2 and water vapour in and out

Short distance so light can penetrate - 1 cell thick, transparent

Protective barrier agianstpp

20
Q

Xylem tissue

A

Type of vascular tissue responsible for the transport do water and minerals

Tissue is composed of vessel elements which are composed of vessel elements - ELONGATED dead cells

Walls of these cells are strengthened with a waterproof material called lignin, which provides structural supporT
NON living

Pits - allow water to leave xylem to get to shoots

21
Q

Phloem

A

Type of vascular tissue

Responsible for transport of organic nutrients particularly sucrose from leaves and stems where it’s made

Composed of volume of sieve tube cels Seperated by perforated walls called sieve plates

Connected to companion cells - ATP for active transport

No nucleus - more space

Both directions

Parenchyma - store food and release chemicals do not eaten by herbivores

22
Q

Organs

A

Collection of tissues that are adapted to perform a particular function in an organism

23
Q

Organ systems

A

Large multicellular organisms have coordinated organ systems

Each organ system is composed of a number of Organs working together to carry out a major function in the body

24
Q

What are stem cells

A

Able to undergo cell division again and again and are the source of new cells necessary for growth development and tissue repair

Once stem cells become specialised they loose the ability to divide entering the g 0 phase if the cell cycle

Activity do stem cells has to be strictly controlled

25
Q

Stem cell potency

A

Ability to differentiate

The greater the number of cell types it can differentiate into the greater the potency

26
Q

Totipotent stem cells

A

Can differentiate into ANY type of cell
Fertilised egg, zygote and the 6 or 16 cells from its first miotic divisions are TOTPOTENT
Destined to eventually produce a whole organism
They can also differentiate into extra-embryonic tissues liek the Anouium and umbilicus
Differentiate into cells which produce the embryo and placenta

27
Q

Pluripotent cells

A

Can form ALL tissue types but not whole organisms

Present in early embryos and are the origin of the different types of tissues within an organism

28
Q

Multi potent

A

The stem cell can only form a range of cells within a certain types of tissue

Haemotopeitic cells in bone marrow are multi potent because this gives rise to various types of blood cell

29
Q

Sources of plant stem cells

A

Meristems/meristematic tissue
Found where growth occurs in a plant E.g. Tips of roots and shoots
Meristematic tissue can be found between phloem and xylem tissue(vascular cambium) Cells found here will DIFFERENTIATE into cells found in xylem and phloem

this allows vascular tissue to grow as the plant grows, the pluripotent nature of stem cells in meristem occurs throughout WHOLE life of plant

30
Q

Sources of animal stem cells - embryonic stem cells

A

An embryo develops from a fertilised egg

All the cells in an embryo start off identical and undifferentiated - they are embryonic stem cells (TOTPOTENT)

31
Q

When do embryonic stem cells change to pluripotent state

A

They can become specialised to form any type of cell by switching gens on and off
Whole new organism develops form embyronic stem cells
After 7 days the mass of cells, BLASTOCYST, it’s in its pluripotent state- remain in this state until birth

32
Q

Adult stem cell - sources of animal stem cells

A

Some stem cells remain in the body of adults , found in limited numbers at certain locations
Can differentiated into related cell types ONLY
E.g. Bone marrow - can only differentiate into blood cells adn cells of immune system
Multi potent, but evidence they can artificially be triggered to be PLURIPOTENT
Can be harvested from umbilical cord ( blood stem cells )

33
Q

Where can adult stem cells be found

A

Brain, eyes, blood,heart, liver, bone marrow, skin, muscle

34
Q

What is differentiation

A

The process of a unspecialised cell becoming specialised and having a specific function

35
Q

Replacement of red blood cells

A

Erythrocytes are ESSENTIAL for oxygen transport
Due to lack of nucleus and organelles - live for only 120 days
Need replacing constantly
Stem cell colonies in the bond marrow produce 3 billion per kg of body mass per day

36
Q

Replacement of white blood cells

A

Neutrophils
Essential role in immune system
Live for around 6 hours and the colonies of bone marrow produce 1.6 billion per kg per HOUR
Figure increases during infection

37
Q

Ethics - stem cells

A

Removal of stem cells from embryos - destruction, live begins at contraception - MURDER
Possibly having another child just so they can use the umbilical cord for stem cells
Adult stem cells- don’t divide as well and are likely to get a mutation
Test on rats adn animals- give them treatments developed by stem cells

38
Q

Uses of stem cells examples?

A

Heart disease - muscle tissue in heart damaged aw a result of heart attack
Type 1 diabetes - pluripotent stem cells to produce glucose responding cells that RELEASE INSULIN
Parkinson’s
Birth defects
Macular disease
Alzheimer’s
Drug trails
Development biology
Burns
Spinal injuries -stem cells to repair spinal cord- repair nerve ends

39
Q

Stem cells - Alzheimer’s

A

Transplanting neurall stem cells into brain of mice = POSITIVE EFFECT
Build up of abnormal proteins

40
Q

Burns - stem cells

A

Stem cell grown on biodegradable meshes can produce new skin for burn patients- quicker than Normal process of taking grade from at other part of the body

41
Q

Development biology - stem cells

A

With their ability to divide indefinitely, and differentiate
Study of changes that occur as multicellular organisms grow and develop from single cell and why things go wrong

BIOLOGY -MODULE 2 (24 decks)

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