Biology Cells: Stuff to memorise

Includes things in chapter 1!

Function of cell surface membrane

Controls movement of substances in and out of cell

Function of cell wall

-Protects cell from injury

-Gives plant cell a fixed shape

Function of cytoplasm

-site of cellular activities

-contains organelles

Function of nucleus

-control cellular activities like cell growth and repair

-essential for cell division 

-nucleus membrane separates nucleus contents from cytoplasm

Function of RER

-RER transports proteins to Golgi body for secretion out of cell

Function of ribosomes

-synthesise proteins in cell

Function of SER

-synthesise substances like fats and steroids

-by detoxification, they make harmful substances harmless

Function of Golgi body

-chemically modify substances made by the ERs

-store and package them in vesicles to secrete out of cell

Function of mitochondria

-release energy for cellular activities like growth and reproduction via aerobic respiration

Function of chloroplasts

-contain chlorophyll for photosynthesis

Function of vacuole

-store dissolved substances

Function of centrioles

-cell division

Define differentiation

process by which stem cells becomes specialised for a function

Function of RBC

-transport oxygen molecules bound with haemoglobin from lungs to cells

Function of muscle cell

-contract to support movement

Function of root hair cell

-absorb water molecules and mineral ions from soil into roots

Structure of cell surface membrane

-partially permeable membrane

-made of lipids and proteins

Structure of cytoplasm

-liquid and streaming structure

Structure of nucleus

-DOUBLE MEMBRANE (nucleus surrounded by nuclear membrane)

-contains genetic info in chromosome form

Structure of chromatin

-each strand has long thread-like structure

-made of proteins and DNA

-condenses and shortens during cell division forming chromosomes which are thick-rod like structures

Structure of RER

-tubular with attached ribosomes

-network of flattened spaces lined with a membrane

-outer surface is continuous with nuclear membrane

Structure of ribosomes

-small round structures made of RNA and proteins

-either lie freely in cytoplasm or attached to RER

Structure of SER

-no ribosome attached

-more tubular than RER and is connected to it

Structure of Golgi body

-disc-shaped flattened spaces surrounded by membranes

Structure of mitochondria

-oval shaped

-DOUBLE MEMBRANE with extensive infoldings

Structure of chloroplasts

-oval-shaped and green

-DOUBLE MEMBRANE

Structure of vacuole

-fluid filled space enclosed by tonoplast (partially permeable membrane)

-numerous and small in animal cells, large central one in plant cells

-contains dissolved substances in cell sap (plants)

Circular biconcave shape (RBC)

Increase surface area to volume ratio which increases rate of diffusion of oxygen in and out of cell

Nucleus absent (RBC)

Allows packing of more haemoglobin for increased oxygen carrying capacity.

Flexible cell surface membrane (RBC)

alteration of shape to allow it to easily squeeze through narrow capillaries

Contains haemoglobin (RBC)

Can reversibly bind to oxygen, continuously transporting it around body.

Many mitochondria (muscle cell)

Release more energy via aerobic respiration for muscle cell’s contractions

Contractile protein fibres (muscle cell)

contract and relax for movement

Elongated, cylindrical shape (muscle cell)

Easily arranged into parallel arrays, increasing the muscle’s strength

Many nuclei (muscle cell)

More synthesis and secretion of skeletal muscle proteins to support increased rate of muscle contraction AND cell division

Long, narrow protusion (RHC)

Increases surface area to volume ratio which increases rate of absorption of water molecules and mineral ions.

Lower water potential in cell sap (RHC)

Maintain steep water potential gradient to allow water molecules to continuously enter cell by osmosis

Many mitochondria (RHC)

More energy released via aerobic respiration which increases rate of active transport to absorb mineral ions

Uniformly thin cell wall (RHC)

Reduce distance for diffusion to increase rate of absorption of water molecules and mineral ions

How do substances made by ER leave the cell?

-vesicles with substances made by RER are pinched off from RER

-they fuse with Golgi body and release contents into it where they may be modified

-secretory vesicles with modified substance is pinched off Golgi body

-they go to cell surface membrane, fuse with it, and release contents out of cell