cell specialization and differentiation and potency

Question 1

define cell differentiation

Answer 1

Differentiation is the development of specialised structures and functions in cells. ​
The process by which cells become specialised to carry out specific functions.

Question 2

what are specialized cells

Answer 2

Cells with specific functions or structures that are different to other cells and have specific roles or tasks.

Question 3

what is a genome

Answer 3

The genome is all the genetic information of an organism. Organisms in the same species share most of their genome
All cells within an organism share the same genome. As a result, all cells in a multicellular organism have the same genes.

Question 4

how does differentiation occur

Answer 4

when certain genes within the cell are expressed or ‘turned off’

Question 5

what are stem cells

Answer 5

cells with the potential to develop into many different types of cells in the body. They serve as a repair system for the body.
these are UNSPECIALIZED UNDIFFRENCIATED CELLS.

Question 6

what is embryonic development

Answer 6

the different stages in the development of an embryo.

Question 7

what are the factors that can change gene expression 4

Answer 7

1. embryonic development
2. external environmental conditions such as heat, light, chemicals.
3. internal environmental conditions - hormones.
4. stem cells

Question 8

define tissues

Answer 8

A tissue is a group of cells that have differentiated in the same way to perform the same function.

Question 9

what are the benefits of cell specialization

Answer 9

1. focus on fewer tasks at once cuz they r specialized for a specific function which allows it to perform that function faster n better.
2. saves energy.
3. They can have a specialized structures and metabolism
4. As they do one (or few) things all the time, they evolve faster in that particular tasks

Question 10

define fertilization

Answer 10

Fertilisation is a multi-step process in which a sperm and egg fuse to form a single cell called a zygote.
Fertilisation occurs in sexually reproducing organisms that produce haploid gametes (D3.1.2), such as plants (D3.1.8) and animals (D3.1.6).

Question 11

what are Embryonic Stem Cells

Answer 11

pluripotent stem cells.
can divide into more stem cells or can become any type of cell in the body. This allows embryonic stem cells to be used to regenerate or repair diseased tissue and organs.

The cells in the zygote and embryo are unspecialised stem cells (B2.3.2).
However, as the cells of the embryo continue to divide, they begin to specialise in structure and function.

Question 12

how does differentiation during embryonic development occur

Answer 12

DNA methylation (D2.2.6) enables the permanent silencing of some genes. At the same time, developmental genes begin to be expressed, differentiating the cells from each other.
pluripotent cells (which r embryonic stem cells)^^^
the general idea is that some pieces of dna is on/off.

Question 13

define cell specialization

Answer 13

when cells Carry out specific functions, more effectively, the end result.
*Cell specialisation allows cells to perform a function with increased efficiency.
Cells can develop into specific shapes and sizes (B2.3.5)
Cells can create proteins needed to carry out specific metabolic reactions.

Question 14

what is gene expression

Answer 14

Gene expression is the the process by which the information encoded in a gene is turned into a function. Often in gene expression, a sequence of DNA (the gene) is transcribed to form RNA (D1.2.1) which is then translated to form a protein (D1.2.5).
basically when a gene becomes a protein.

Question 15

what is the step-by-step process by which cells differentiate?

Answer 15

1. you have a single cell
2. this changes to two identical daughter cells
3. there is an expression of a certain gene within that cell (this depends on the morphogen gradient, and the potency of the cell - if its a stem cell ob).
4. that gene performs that specific function in that specific location of the body.

Question 16

what happens in the early embryo? what do these cells secrete?

Answer 16

morphogens - form-giving molecules - shapes, function, location, role.
these morphogens/chemicals diffuse outwards, from the cell, and then a concentration gradient is established.

Question 17

what are morphogens

Answer 17

A chemical in the cell the concentration gradient of which determines the fate of surrounding cells.
*Morphogens are signaling molecules that direct cell fate decisions in a concentration-dependent manner. Morphogens control proliferation, differentiation, and patterning during embryonic development to orchestrate the formation of tissues and organs.
ex: retnoic acid.

Question 18

what happens to the other/surrounding cells when morphogens r relessed form a cell

Answer 18

they determine the distance in the concentration gradient (how many morphogens have affected it) thru receptors on the cells surface, which then determines the cells’ fate.
eg. if the cell is closer to the morphogen releasing cell it is most likely to have a function close to the area of which the morphogen was released, for ex, if the morphogen cell is closer to the skin and outside of the body, and the other cell is too, its job would most likely be something to do with protecting the skin or helping fight off bacteria n shit. - this is only with stem cells

Question 19

what is stem cell potency

Answer 19

diff types of stem cells, and their rules n regulations as to what cell it can specialize in to. - bcz not all stem cells have the ability to differentiation into new types of cells as told by the morphogens and the concentration gradients.

Question 20

what are the types of potencies stem cells can be, there r 4?

Answer 20

1. totipotent - give rise to an organism, diff into any typa cell including placental cells.
2. pluripotent - diff into any typa cell but cant give rise to an organism - embryonic stem cells (eg).
3. multipoint - only diff into closely related body cells (bone barrow or umbilical cord, cant give rise to all types of blood cells etc).
4. unipotent - diff into only 1 typa cell - associated cel type (specific type of cell they are meant to be in the body) - whatever the body needs - ex. if u were a liver cell u can only diff into another liver cell.

Question 21

what typa cell potency do we have at the morula?

Answer 21

totipotent stem cells as they not only can differentiate into any cell of the organism, but they can also give rise to the embryo, the placenta and the embryonic sac tissues.

Question 22

what typa cell potency do we have at the blastocyst, aft morula when it develops?

Answer 22

pluripotent stem cells as they cannot generate an entire organism, but are able to differentiate into any of three ‘germ’ layers. These layers are the endoderm (inner layer), the mesoderm (middle layer) and ectoderm (outer layer).

Question 23

what is the stem cell niche?

Answer 23

The stem cell niche can be thought of as the microenvironment within the organism in which the stem cells live and receive their instructions

Question 24

what are the interactions that can determine what happens to the stem cells in the niche, describe the step by step

Answer 24

Signalling molecules can activate, or prevent genes from transcribing (see subtopic B2.2). This leads to some cells being instructed to remain dormant (inactive) while others are directed to make more of the same kind of stem cell. Still others become differentiated into another kind of cell.

Question 25

what regulates gene expression?

Answer 25

regulated by proteins that bind/stick to specific base sequences in DNA

Question 26

how is cell size as an aspect of specialization.

Answer 26

Cell specialisation allows cells to perform a function with increased efficiency.
Cells differentiate to develop into specific shapes and sizes that maximize the ability of the cell to perform its specialise function. The structure of these cells is linked directly to their function.

eg: The spherical human egg cell has evolved to be large and highly specialised so that it contains all the nutrient materials needed for the early development of the embryo. The sperm on the other hand does not need such nutritional content and so remains small. See subtopic A2.2 for more about cell structure.

Question 27

what do cells needa do before they devide n diff?

Answer 27

Cells need to grow before they divide. However, they do not keep growing indefinitely. Cells have control mechanisms involving cell surface receptors and growth factors in the surrounding environment to ensure that the maximum size of any given cell type is consistent within an organism.

Question 28

true or false: The larger the cell becomes, the more the SA:V ratio reduces.

Answer 28

true. SA:V means there is more volume n less surface area to cover up for it.
When there is a larger SA:V, it is easier for nutrients to pass into the cell and for excretory products to exit the cell.