Ch 1 - cells Flashcards
What are cells?
- Cells are the building blocks of life.
- The simplest structural and functional units of life
How do we study the parts of a cell?
We use light microscopes and electron microscopes.
How much does a light microscope magnify up to?
A light microscope can magnify up to 1000x.
How much does an electron microscope magnify up to?
An electron microscope can magnify more than 200,000x.
What are the pictures taken by microscopes called?
Micrographs
What are the 2 types of cross sections of a cell?
Longitudinal section and transverse section
How does cutting a cell 2 different ways help?
It helps to create a 3D picture of the cell
What is protoplasm?
A complex jelly-like substance, consisting of the cell membrane, cytoplasm, and the nucleus
Function of protoplasm?
Provides a site for many chemical activities that allow the cell to:
1. survive
2. grow
Description of cell membrane?
- Made up of lipids (fats) and proteins
- A partially permeable membrane
Function of cell membrane?
- Controls the movement of substances in and out of the cell, through its partially-permeable membrane
Description of cell wall?
- Encloses the entire plant cell, enclosing the cell membrane
- Made up of cellulose (a type of carb) and is fully permeable
Function of cell wall?
- Protects the cell from injury
- Gives the plant a fixed shape
Description of cytoplasm?
- A jelly-like substance that fills the inside of the cell
- Enclosed by the membrane
- Contains organelles
Function of cytoplasm?
Provides a site for cellular activities
What are the different organelles found in the cytoplasm?
Nucleus, Ribosomes, Smooth Endoplasmic Reticulum (SER), Rough Endoplasmic Reticulum (RER), Golgi body, mitochondria, chloroplasts, vacuoles
Description of the nucleus?
- Surrounded by a membrane called the nuclear membrane
- Contains genetic info. in the form of chromosomes
Description of chromatin?
- Long thread-like structure found within nucleus
- Made up of proteins and a compound called DNA
- The DNA carries instructions that a cell needs for carrying out its activities
- The chromatin condenses and shortens to become thick, rod-like structures during cell division
- A human contains 46 chromosomes –> 23 pairs, 23 (mom) & 23 (dad)
Description of nuclear membrane?
- Separates the contents of the nucleus from the rest of the cytoplasm
Description of RER?
- Consists of a network of flattened spaces lined with a membrane
- Appears rough on the outside due to ribosomes attached to its outer surface
- The outer surface of RER is continuous with the nuclear membrane
Is the RER connected to the nuclear membrane?
YES
Function of RER?
- RER provides a site for ribosomes to be attached to
- transports proteins made by ribosomes to the Golgi body for secretion out of the cell
Description of ribosomes?
- small round structures
- either attached to RER’s membrane or lie freely in the cytoplasm
Function of ribosomes?
- ribosomes attached to RER synthesise proteins that aare transported out of the cell
- ribosomes lying freely in the cytoplasm synthesise proteins tose be used iwth in the cytoplasm of that cell
Description of SER?
- does not have ribosomes attached to it membrane
- smooth
- more tubular than RER
Function of SER?
synthesises substances such as fats and steroids
- converts harmful substances into harmless substances through detoxification
Description of Golgi body?
- shaped like a disc
- consists of flattened spaces surrounded by membranes
- vesicles can be seen fusing with one side of the Golgi body and pinching off from the opposite side
Function of Golgi body?
- chemically modifies substances made by the ER
- stores and packages these substances in vesicles for secretion out of the cell
Description of mitochondria?
small oval-shaped organelles
What is differentiation?
differentiation is the process by which a cell becomes specialised for a specific function
Adaptation of red blood cell?
contains haemoglobin which binds to oxygen
