Module 2 (Cells) Revision Notes
Kingdoms in Biology?
Living Organisms can be placed into 5 groups
(Animal, Plant, Bacteria, Fungi, Protoctista)
Animal and Plant are Multicellular Organisms
(made up of billions of cells working together)
Bacteria, Fungi, Protoctista are Microorgansism (made up of one or a few cells)
[note: Viruses are not defined as living organisms because they do not have the
standard components of a cell – acellular, and cannot perform MRS GREN without
a host]
all living organisms are made from cells (multicellular = millions, microorganism =
one/few), all cells have 4 properties = DNA, ribosomes, cytoplasm, cell membrane
Eukaryotic vs Prokaryotic Cells?
Eukaryotic = animal/plant cell, has membrane bound organelles (nucleus, endoplasmic
reticulum, golgi body, lysosome, mitochondra)
Prokaryotic = bacteria, has no membrane bound organelles
What are the 2 forms of Reproduction?
Sexual & Asexual
Sexual Reproduction in Animals & Some Plants
Asexual Reproduction in Microorganisms & Some Plants
Sexual Reproduction uses 2 parents (each provides a gamete which fuse to form a
zygote, zygote develops into organism)
Asexual Reproduction uses 1 parent to produce genetically identical offspring
How does a Zygote develop into an Organism?
Zygote is a stem cell
stem cell = undifferentiated/unspecialised cell, can form any type of cell
zygote divides by mitosis to make many stem cells
each stem cell differentiates into specialised cell
each specialised cell divides by mitosis to make many copies and form a tissue
different tissues join to form an organ
different organs join to form an organ system
this is surrounded by the Body
Define a tissue, organ and organ system?
tissue = a group of specialised cells
organ = made of different tissues
organ system = different organs working together
What is an Animal Cell made of?
, Organelles (nucleus, endoplasmic reticulum, golgi body, lysosomes, mitochondria,
ribosomes) – all have membrane except the ribosomes
Cytoplasm (site of chemical reaction)
Cell Membrane (holds cell contents together, controls what enters/leaves cell, cell
signalling)
Structure of Nucleus?
contains DNA (made of genes, genes code for making proteins)
DNA wrapped around histones to form Chromatin
nucleus has a double membrane, called Nuclear Envelope, which contains pores
at centre of nucleus is Nucleolus – produces mRNA (copy of a gene)
rest of nucleus made of Nucleoplasm (contains the DNA/chromatin)
Endoplasmic Reticulum?
2 types = Rough and Smooth
Rough Endoplasmic Reticulum has ribosomes on it, makes proteins
Smooth Endoplasmic Reticulum has no ribosomes on it, makes lipids/carbohydrates
Golgi body?
modifies and packages proteins
packages them into vesicles for transport
digestive enzymes are placed into lysosomes (vesicles with membranes around them)
Mitochondria?
site of respiration, releases energy, produces ATP (energy carrier molecule)
has a double membrane, inner membrane folded into Cristae (increases surface area for
enzymes of respiration)
middle portion called Matrix
Ribosomes?
attached to RER
site of protein synthesis
What is a Plant Cell made of?
Organelles (nucleus, endoplasmic reticulum, golgi body, lysosomes, mitochondria,
chloroplast, vacuole, ribosomes) – all have membrane except the ribosomes
Cytoplasm (site of chemical reaction)
Cell Membrane (holds cell contents together, controls what enters/leaves cell, cell
signalling)
Cell Wall (made of cellulose, prevents cell from bursting or shrinking)
Structure of chloroplast?
