Chapter 7: Units of life Flashcards
What is a cell?
The basic units for all living organisms
What is cell theory?
It states that:
- Cells are the smallest, living organisational unit
- All organisms are formed by cells
- All cells come from pre-existing cells
What is the cell membrane?
It is a layer of phospholipid that encloses the cytoplasm. It allows things to the transported in and out of a cell while keeping it separate from other cells.
What is cytoplasm?
A jelly-like substance that fills the space between organelles.
What is cytosol?
It is the fluid component to cytoplasm.
What is DNA?
It contains genetic and hereditary information. It also directs activities.
What are flagella?
It is whip-like and can act as a propeller to move the cell.
What are cilia?
These are small and hair-like and act like oars to move the cell.
What are the two main types of cells?
Prokaryotes
Eukaryotes
What are prokaryotes?
These are small and have one cell
Scattered ribosomes
Not bound to membrane wall
Have a cell wall made of protein
The cell performs all functions itself without specialisations.
What are eukaryotes?
These have DNA in the nucleus in the form of chromosomes
They have organelles
What are the main differences between prokaryotes and eukaryotes?
Prokaryotes are single-celled
Prokaryotes are not bound to a membrane wall
Eukaryotes have organelles
What is solely inside a plant cell?
Cell wall made of cellulose
Large vacuole
Plastids
What is solely inside an animal cell?
Centriole
What is the cell wall?
These are only found in plant cells and are non-living cellulose structures outside the cell membrane. It provides support.
What is lignin?
Provides support for woody plants
What is a centriole?
Small, cylinder structures that are composed of microtubules and separate chromosomes during cell division.
What is the smooth endoplasmic reticulum?
It is a network of membranes that link the organelles in a cell. It does not have ribosomes.
What is the rough endoplasmic reticulum?
It is a network of membranes that link the organelles in a cell. It has ribosomes.
What is the golgi apparatus?
It is responsible for the packaging, distribution and transport of proteins.
What are the lysosomes?
They are found in animal cells and have enzymes that break down foreign material and debris. It can also break down its own cell.
What are the mitochondria?
They are the powerhouse of the cell. They transform energy to be used by the cell.
What is the nucleus?
A large organelle that has the DNA for the cell.
What is the nuclear membrane?
It surrounds the nucleus and has pores to allow the nucleus to communicate with other organelles.
What are ribosomes?
Sites where proteins are packaged.
What are vacuoles?
These are membrane-bound and contain food, enzymes and fluid.
What are vesicles?
These transport substances within the cell.
What is a contractile vacuole?
These are found in protists and pump out excess water.
What is a food vacuole?
These are formed by cellular eating and are a part of amoebas.
What is phagocytosis?
Cellular eating
What is pinocytosis?
Cellular drinking
What is endocytosis?
Brining in
What is exocytosis?
Expelling out
What does the development of the cell include?
Cell division
Cell growth
Cell differentiation
What is cell differentiation?
This is where cells take on specialised functions to perform different roles within an organism.
What happens to the DNA not used during cell differentiation?
It is simply “switched off” and not used. The cell still retains the genetic code for all types of cells.
What do all cells begin as?
Stem cells
What is the cellular environment?
This is where unicellular organisms live
What is a protist’s cellular environment?
Protist’s can only move from one environment to the next
They either tolerate the conditions for die
What is the extracellular environment?
This is the area outside an individual cell in a complex organism
What must a cell in a complex organism do to survive?
They must exchange carbon dioxide, oxygen, nutrients from food and waste removal.
What must a cell do to function efficiently?
They must control salt, temperature, waste and pH.
What are phagocytic cells?
These remove dead cells
How can cells die
Conditions become unbearable
Commit suicide
What is cell suicide also known as?
This is known as physiological or programmed cell death.
What are all things made up of?
Hydrogen, carbon, calcium and nitrogen
What are the 2 types of compounds?
Inorganic and organic
What are the 4 types of INORGANIC compounds?
Water
Oxygen
Carbon Dioxide
Minerals
What properties make water useful in chemical reactions?
Cohesion
Adhesion
High Heat Capacity
What is adhesion?
The water molecule can stick to other molecules.