Chapter 3 Flashcards
What is the cell theory?
The principle that all living things (organisms) are made up of a cell; also called plasma membrane
Quick note on cells
- living organisms; including humans, are made up of cells and the materials produced by cells.
- cells are the basic structural and functional units and plants and animals
- this is the basic principle of biology; cell theory
- all cells are very small - so small that you need a microscope to see most of them
- they vary in shape and size
- despite variations human cells are similar
What is the cell membrane
It the plasma meme brand which surrounds the cell and forms the outer boundary of the cell.
It separates the cells from its neighbours and external environment.
Made up of a phospholipid bilayer which determines what gets in and out.
Cytoplasm
Cytoplasm Is a thick fluid that fills the inside of the cell and the suspended structures it contains
Cytosol
Cytosol is the liquid part if the cytoplasm (75-90%)
Organelles
Organelles are the structures suspended in the cytoplasm that carry out specific functions
A cytoskeleton
A cytoskeleton or internal scaffolding of protein fibres within the cytoplasm.
It consist of microfilaments and microtubules that give the cell its shape and assist with the movement of material, organelles or the whole cell.
Microtubules = hollow rods that keep organelles in place or move them around the cell
Microfilaments = which move materials around the cytoplasm or moves the whole cell
Inclusion
Inclusions are substances that are not path of the cell structure but are found as chemical substances occurring as granules or liquid droplets is the cytoplasm.
Haemoglobin in rbc, pigments in cells of skin,hair and eyes
Mitochondria
Mitochondria are spherical or elongated structures spread through the cytoplasm.
They have a double membrane - outer is smooth and inner is folded in towards the centre of the mitochondrion. Mitochondria realises energy for the cell through the process of respiration. (Power House of the cell)
Nucleus
- usually a void or sphere that contains genetic material, mostly DNA
- it is separated from the cytoplasm by the NUCLEAR MEMBRANE
- the membrane is double (2 membranes separated) and has gaps called NUCLEAR PORES through which large molecules can pass through
- An area called the NUCLEOLUS is composed mainly of RNA. The DNA and nucleolus are suspended in a jelly like NUCLEOPLASAM
- largest
Golgi Body
Golgi body or apparatus is flattened, membranous bags staked on top of each other. They modify proteins and packaged them in vesicles for the secretion from the cell.
Vesicles are punished off from the edges of the membranes.
Lysosomes
Lysosomes are small spheres that contain enzymes able to break down proteins, lipids, nucleic acid and some carbohydrates.
Contains digestive enzymes that are able to break down large molecules
*lysosomes can join vesicles and break down the material in it
Lysosomes break down materials that are taken I give the cell or breaks down worn out organelles
Ribosomes
Ribosomes are very small and spherical.
They may be free in the cytoplasm or attached to the membranes.
amino acids joined together at the ribosomes to make proteins
Endoplasmic reticulum .
ER - pairs of parallel membranes extending through the cytoplasm and connecting the cell membranes with the nuclear membrane.
Provides a surface on which chemical reactions occur.
The channels between the paired membranes are used for storage or transport of materials
Rough Er - ribosomes on them
Smooth Er - no ribosomes on them
Centrioles
Centrioles are pairs of cylindrical structures usually located near the nucleus; involved in the reproduction of the cell
