Biology paper 1 edexcel GCSE 9-1

Biology notes Paper 1

Key concepts of biology 1.1 – 1.17

·         Animal cells, plant cells and bacteria cells

 

 

 

                                                                

·         Cytoplasm: contains a watery jelly and is where most of cells activities occur

·         Nucleus: controls the cell, inside is chromosomes which contain DNA

·         Cell membrane: like a very thin bag, controls what enter and leaves the cell, separates one cell from another

·         Mitochondria: jelly bean shaped structures, in which aerobic respiration occurs ‘power house’ of the cell

·         Cell wall: made of cellulose and supports and protects the cell

·         Vacuole: large permanent vacuole which stores cell sap, keeps cell firm and rigid

·         Chloroplasts: contain chlorophyll which traps energy from the sun. The energy is used for photosynthesis

 

 

 

 

 

 

·         Extra in a bacteria cell there is the DNA and Flagellum

·         DNA is the fundamental and distinctive characteristics or qualities of someone or something, especially when regarded as unchangeable.

·         A flagellum is like a tail off the cell to allow it to move.

·         Specialised cells

·         Different cells have different functions

-          Multicellular organisms contain lots of different type of cell

-          Cells that have a structure which makes them adapted to their functions are called special cells

-          Some examples are: egg, sperm and ciliated.

·         Egg cells:

-          Main functions are to carry female DNA and nourish developing embryo

-          Contains nutrients in cytoplasm to feed embryo

-          Has haploid nucleus

-          Ability to quickly change structure after fertilization

·         Sperm cell

-          Main function is to transport the males DNA to females egg

-          Sperm has long tail so it can swim

-          Lots of mitochondria for energy

-          Haploid nucleus

·         Ciliated  epithelial cells

-          Line the surface of organs

-          Some have cilia – hair like cells on top of surface

-          Function is to move substances

-          E.g. some in throat to help move mucus so you don’t cough

·         Microscopes

·         Electron microscopes were made in 1930 and use electron rather than light, they have a higher magnification and resolution than light microscopes

·         Because of this they let us see smaller things through the microscope and in much more detail

·         These microscopes have allowed us to see the internal structures of mitochondria and chloroplasts

·         This has allowed us to have a greater understanding in our knowledge

·         Light microscopes were invented in 1950 and they work by passing light through the specimen.

·        

Prefix

Effect on unit

Example

Milli-

Millimetres (mm)

Micro-

Micrometres (µm)

Nano-

Nanometres (nm)

Pico-

Picometres (pm)

·         We need to know the SL units which are :

 

 

 

 

·         Enzyme action

·         Chemical…