Cell Structure Flashcards
Cell Theory #1
Living organisms are composed of cells
Cell Theory #2
Cells are the smallest unit of life
Cell Theory #3
Cells come from preexisting cells
All cells must have these features
-must have a plasma membrane
Every living cell is surrounded by a membrane, which separate cell contents from everything else outside
-A cell contains genetic material which stores all the instructions needed for the cell’s activities.
-Many of these activities are chemical reactions, catalyzed by enzymes produced inside the cell
-Cells have their own energy release system that powers all of the cell’s activities. (respiration to release energy) in the form of ATP
In other words: Plasma Membrane, genetic material, enzymes and energy release system
What is a singled cell called?
Unicellular
What is more than one cell called?
Multicellular
When is one cell considered itself a separate organism?
When it is able to grow, reproduce and perform basic functions needed to survive.
What are the 7 functions of life?
Nutrition, growth, response, excretion, reproduction, metabolism, homeostasis
Atypical Cells
Skeletal muscle- Each cell can be up to 30 cm long and hold hundreds of nuclei (long and a lot of nuclei)
Acetabularia grows up to 10cm but only 1 nucleus (unicellular)
What is Aseptate Fungal Hyphae?
Aseptate fungal hyphae are long threads (hyphae) with many nuclei. They have no dividing cell walls, called septa (singular: septum). The result of this is shared cytoplasm and multiple nuclei (singular: nucleus). This challenges the idea that a cell is a single unit as the fungal hyphae have many nuclei, are very large and possess a continuous, shared cytoplasm.
Metabolism - Function of life definition
The regular set of life-supporting chemical reactions that takes place within the cells of living organisms.
Growth - Function of life definition
An increase in size or shape that occurs over a period of time.
Response (to a stimulus) -Function of life definition
A reaction by the living organism to changes in the external environment.
Homeostasis - Function of life definition
The maintenance of a constant internal environment by regulating internal cell conditions.
Nutrition - Function of life definition
The intake of nutrients, which may take different forms in different organisms. Nutrition in plants involves making organic molecules (during photosynthesis), while nutrition in animals and fungi involves the absorption of organic matter.
Reproduction - Function of life definition
The production of offspring, either sexually or asexually, to pass on genetic information to the next generation.
Excretion - Function of life definition
The removal of waste products of metabolism and other unimportant materials from an organism.
What is an example of a unicellular organism?
Paramecium and Chlamydomonas
Metabolism for Paramecium and Chlamydomonas.
Most metabolic reactions are catalysed by enzymes and take place in the cytoplasm.
Growth for Paramecium
As it consumes food, the Paramecium enlarges. Once it reaches a certain size it will divide into two daughter cells.
Growth for Chlamydomonas
Production of organic molecules during photosynthesis and absorption of minerals causes the organism to increase in size. Once it reaches a certain size it will divide into two daughter cells.
Response for Paramecium
The wave action of the beating cilia helps to propel Paramecium in response to changes in the environment, e.g. towards warmer water and away from cool temperatures.
Response for Chlamydomonas
Chlamydomonas senses light changes in its environment using its eye spot and then uses its flagella to move towards a brighter region to increase the rate of photosynthesis.
Homeostasis for Paramecium and Chlamydomonas
A constant internal environment is maintained by collecting excess water in the contractile vacuoles and then expelling it through the plasma membrane. This process is called osmoregulation and helps Paramecium and Chlamydomonas to maintain their water balance.
Nutrition for Paramecium
Paramecium is a heterotroph. It engulfs food particles in vacuoles where digestion takes place. The soluble products are then absorbed into the cytoplasm of the cell. It feeds on microorganisms, such as bacteria, algae and yeasts.
Nutrition for Chlamydomonas
Chlamydomonas is an autotroph; it uses its large chloroplast to carry out photosynthesis to produce its own food.
Reproduction for Paramecium
It can carry out both sexual and asexual reproduction, though the latter is more common. The cell divides into two daughter cells in a process called binary fission (asexual reproduction).
Reproduction for Chlamydomonas
It can carry out both sexual and asexual reproduction. When Chlamydomonas reaches a certain size, each cell reproduces, either by binary fission or sexual reproduction.
Excretion for Paramecium
Digested nutrients from the food vacuoles pass into the cytoplasm, and the vacuole shrinks. When the vacuole, with its fully digested contents, reaches the Paramecium’s anal pore, it ruptures, expelling its waste contents to the environment.
Excretion for Chlamydomonas
It uses the whole surface of its plasma membrane to excrete its waste products.
Definition of Heterotroph
A heterotroph is an organism that feeds by taking in organic substances (usually other living things).
Definition of an
Autotroph
An autotroph is an organism that can produce its own food from inorganic sources.
