UNIT 2 - B 2.3 - Cell Specialization Flashcards
What allows multicellular organisms to grow and allows the replacement of dead/damaged cells?
cells having the ability to reproduce themselves
What do multicellular organisms usually start their existence as?
a single cell called a zygote
What is a zygote formed as a result of?
ferilization
What are gametes?
The two cells that fuse in sexual reproduction
How much genetic material does gamete have compared to a zygote?
one half
What is the development progression for humans?
gametes, zygote, embryo, foetus, infant
What does the process of zygotes rapidly starting to differentiate result in?
the formation of specialized cells
What is the differentiation process a result of?
the expression of some genes but not others
What does the cell’s development in a specific matter depend on?
which genes become active
What does the genes activation depend on?
the signal that the cell recieves
What is cell signaling?
The process where information is transferred from the cell surface to the nucleus of a cell
What is cell signalling essential to?
controlling gene expression/differentation
What are morphogens?
signal molecules that control cell differentiation
Where do morphogens occur?
in gradients in different regions of the early embryo
What controls the regional development of the first cells into head and tail structures?
The concentration of the signal molecules (morphogens)
What is different genes being expressed in different parts of the embryo a result of?
The gradient of the signalling molecule (morphogens)
What results in different genes being expressed in different parts of the embryo?
differnent parts of the embryo develop different features
What happens with signalling molecules as the embryo develops?
other signalling molecules become factors in differentiation
What are examples of types of cells that have a diminished ability to reproduce once they become specialized/lose ability all together?
nerve and muscle cells
What type of cells retain their ability to reproduce quickly throughout their life?
epithelial cells such as skin cells
What type of cells are formed from cells that rapidly reproduce?
The same type as the orginal cell
Which type of cells retain their ability to divide and differentiate into different types of cells?
Stem cells
What do stem cells’ ability to divide and differentiate along different pathways result in?
organisms to possess all the types of cells
Where are stem cells found in plants?
Regions of meristematic tissue
where is meristematic tissue found in plants?
near root and stem tips
What are meristematic tissues made of?
rapidly reproducing cells which become various types of tissues within the root or the stem
What do stem cells produce when they divide to form a type of tissue?
daughter cells which stay as stem cells
What is self-renewal?
a process that allows continual production of a type of tissue while also providing continuation of stem cells
What are the two unique properties of stem cells?
The can self-renew and they can recreate functional tissues
What are the possible outcomes of a stem cell dividing?
both daughter cells remain as stem cells, both a stem cell and differentiated cell are formed, or both cells are differentiated
When do cells become differentiated?
when cell signalling ensures that specific genes are expressed as the cell develops
What are stem cell niches?
locations where stem cells are present in high numbers but also demonstrate differentiation
What are examples of stem cell niches in humans?
bone marrow and hair follicles
In bone marrow, where are the stem cells that produce blood cells found?
alongside self-renewing stem cells
What transports differentiated cells away as blood cells are produced?
a large array of supporting blood vessels
Where do hair follicles exist?
in the skin
What are found in the bottom, rounded area of a hair follicle?
large numbers of epithelial stem cells
What are multipotent epithelial stem cells involved with?
hair growth, skin and hair follicle regeneration, the production of sebaceous (oil producing) glands associated with hair follicles
What are the different types of stem cells?
totipotent, pluripotent, multipotent, and unipotent
What are the main characteristics of totipotent stem cells?
they are capable of continued division, have the ability to produce any tissue in organism, only exist in early stages of embryo development, may form a complete organism
What are the main characteristics of pluripotent stem cells?
they come from totipotent cells, only exist in early embryonic stages, can become almost all cell types, cannot produce complete organism
What are the main characteristics of multipotent stem cells?
only forms a limited number of cell types, occur later in development of embryo, present during remainder of organism’s life