BIO - Organisms Flashcards
(19 cards)
What is involved in the process of cell differentiation
As cells increase in number and position they gradually have different genes “turned on” and other genes are “turned off,”‘allowing for them to become cells with a special structure and function. This is known as Cell Differentiation.
Define zygote
A single cell that forms after fertilization that contains all the genetic information needed to form all the different types of cells in an organism.
All sexually reproducing organisms are derived from this type of cell.
What are General Purpose genes?
These genes must operate in all cells eg. Genes responsible for enzymes involved in respiration.
Cell types
Stem cells
Stem cells are non-differentiated cells with the potential to develop into any other cell type.
Cell types
Epithelial cells
Epithelial cells join together to form the outer or inner lining of organs and provide some protection.
Cell types
Red blood cells
Blood cells are formed from the differentiation of stem cells in bone marrow. Red blood cells lose their nuclei before entering the bloodstream and assume the typical bioconcave disc shape (max. O2 and easy movement)
No nucleus > not many enzymes > can’t control shape > live for 100 days > replaced
Cell types
White blood cells
Blood cells are formed from the differentiation of stem cells in bone marrow. White blood cells have different functions involved with the immune system.
Phagocytes use phagocytosis to engulf and destroy bacteria
Other white blood cells make specific antibodies (proteins) in response to bacterial or viral infections, thus rendering pathogens ineffective
List five different types of cells
- stem cells
- epithelial cells
- blood cells
- muscle cells
- nerve cells
List four types of tissues
- epithelial tissue
- connective tissue
- muscle tissue
- nervous tissue
What are tissues comprised of
Tissues are comprised of different cells of the same type. Eg. Epithelial tissue is made up of closely packed epithelial cells
How are organs comprised in a multicellular organism
In a multicellular organism, different tissues combine to form organs.
Eg. Heart made up of muscle, epithelial, nervous, and connective tissue
Name the organ systems
RICH NERDS
Respiratory, immune, cardiovascular, hormonal, nervous, excretory, reproductive, digestive, skeletal
Sensory organs
In order to survive and reproduce, an organism must detect and respond to changes in its environment. They do so using sensory organs which in turn send messages to the central nervous system (CNS) via sensory nerves.
The major sensory organs are skin (pressure and temp), eyes (light), ears (sound), nose (smell) and tongue (taste).
Effector organs
These are always muscles or glands. In the transmission of the message, nerves or hormones can be involved.
Stimulus Response Model (general model)
STIMULUS: a detectable change in the environment (detected by sensory organs)
RECEPTOR: the detector of the change, refers to our senses (receptors in sensory nerves)
MESSAGE: this refers to the method of the message transmission. Can be nervous, hormonal or both
EFFECTORS: muscles or glands (or both)
RESPONSE: the changed conditions
Negative feedback
Negative feedback is a process that maintains control and keeps body systems operating within set limitations. This is called homeostasis.
Examples include: temperature control, blood glucose levels, hormone levels
negative feedback is when the response reverses the stimulus
Reflex arc (example of stimulus response)
The reflex arc is an example if an instant response and involves only nervous messages (therefore the brain is not involved)
- Stimulus is from internal or external changes
- stimulus is detected by receptors
- electrical message moves along the sensory nerve (stimulus) to the CNS and then via intermediate nerves to the motor nerve
- the electrical message then moves to effector muscles and they contract, leading to a response
Examples include getting pricked or burnt
Temperature control
TOO HOT
S: too hot
R: therms receptors in skin or hypothalamus
M:both nervous (sweat) and hormonal (drop in metabolic rate
E: thyroxine/adrenalin levels dropped and sweating begins. Metabolic rate decreases and blood vessels dilate.
Temperature control
TOO COLD
S: too cold
R: therms receptors in skin or hypothalamus
M:both nervous (shiver) and hormonal (increase in metabolic rate
E: thyroxine/adrenalin levels increased and muscles move (to shiver).
Metabolic rate increases and blood vessels constrict.
