A2.2 Cell structure

1)All organisms are composed of cells
2)Cells are the smallest units of life
3)All cells come from pre-existing cells

. 1. DNA as genetic material.

2. Cytoplasm composed mainly of water.

3. Plasma membrane composed of lipids.

cell wall, plasma membrane, cytoplasm, naked DNA in a loop and 70S ribosomes.

plasma membrane(cell membrane)
compartmentalized cytoplasm
nucleus
Chromosomes
Histones
Double membrane with pores;
mitochondria
endoplasmic reticulum
Golgi apparatus
lysosomes
variety of vesicles
Cytoskeleton
microtubules
microfilaments

Structure:
made of:
Peptidoglycan(bacteria)
Pseudo-peptidoglycan(archaea)
Cellulose(plants)
Function:
Protects cells against toxins
Resits osmotic pressures
maintains the shape of the cell

Structure:
Double layer of lipids made of phospholipids
The phospholipid head is hydrophilic; tail is hydrophobic
Function:
separates the interior from the outside environment
controls what enters and exists

Structure:
Water-based
contains: ions, organic molecules, DNA, and ribosomes
Function:
maintains an environment for cellular organism
storage
cell shape
where metabolic reactions occur

Structure:
double-stranded DNA in a loop or circle
Function:
stores info for protein synthesis
molecule of inheritance

Structure:
in cytoplasm
made of 2 subunits(50s large, 30s small)
made from RNA
Function:
translation occurs
reads mRNA > catalyzes the formation of peptide bonds in amino acids > produces proteins for cellular processes

Structure:
Aqueous solution
seperate cell organelles
Function:
suspends ions, organic molecules, orgenelles and ribosomes
metabolic reactions occur
divde cell into specialized parts
seperate conidition for each organelle and increases efficenency
protects part of the cell

Structure:
two subunits; 60s large and 40s small
conisit of rRNA and proteins
bigger than 70s ribsomes
Function:
translation occurs(protein synthesis)
ribsomes read RNA > synethesises proteins > forms polypeptide

Structure:
membrane bound
contains matrix and nuclealus
surrounded by endoplasmic reticulum
Function:
control center of cell
holds genetic material
manages, growth, metabolism and reproduction

Structure:
histones are type of protein
Function:
histones wrap around dna > organizes dna into chromosmes
controls activity of gene
allows for DNA to accuratly be copied through cell division

Structure:
membrane pierced with pores
allows passage of molecules
Function:
seperates and regulate molecules transportation between cucleus and cytoplasm
allows selective movement of ions, RNA, proteins and other molecules
partial involvement in cell division

Structure:
Interconnected membrane form sacs
two types: Rough and smooth ER
Function:
Rough ER
- ribosomes in rough ER does protein synthesis
Smooth ER:
- Involved in lipid synthesis(ex, phospholipids and cholesterol)

Structure:
Found near nucleus
membrane bound
Function:
converts and packages proteins and lipids for transport
air bubbles(vessicals) move materials in and out

Structure:
large, outside cell
membrane bound
filled with cell sap
in plant cell takes up 80%
Function:
stores: salts, minerals, pigments, water, protein, waste product
structural support
regulates internal PH

Structure:
surrounded by membrane
contains digestive enzymes(acidic(low PH))
Function:
waste disposal system
vreaks down older materials + molecules from sinde and outside the cell
Helps in cell death
damage cells "self destruct"

Structure:
filaments that inerconnect inside the cell
composed of protein, "microtubules"
Function:
cell shape + resisitance
organizes parts of cell
basis of cell movement + cell division

HOMEOSTASIS
METABOLISM
NUTRITION
EXCRETION
GROWTH
RESPONSE TO STIMULI
REPRODUCTION

Animals Have:
Cell wall:
None

Fungi have:
Cell wall
present: composed of chitin

Plant have:
Cell wall
Present: composed of cellulose

Animals
Small and transient- used to expel excess water or digest food or pathogens
Plants
Large, permanent vacuole- used for storage of substances and pressurising the cells.
Fungi
Large, permanent vacuole- used for storage of substances and pressurising the cells.

Animals
None
Plants
Contains chloroplasts and amyloplasts.
Fungi
none

Animals
Used to construct spindle in mitosis and control microtubules in cilia and flagella
Plants
None (except in those with male gametes that swim using flagella)
Fungi
None (except in those with male gametes that swim using flagella)

Animals
Present in many animal cells, e.g. sperm
Plants
None (except in those with male gametes that swim using flagella)
Fungi
None (except in those with male gametes that swim using flagella)

Nucleus and most other cell contents break down to facilitate movement of sap through the phloem.
Adjacent companion cells help sieve tube elements stay alive.

Large, multinucleated structure where columns of cells have fused together (syncytium).

No nucleus to increase oxygen carrying capacity whilst being smaller and more flexible.

Large, multinucleated structure without divisions (septa) between cells.

Cells that don't have features normally found in all cells or they have an aditional features besides the features found within a cell

Metabolism​: Catalysized by the enzymes in the cytoplasm
growth: Enlarges as it consumes food, splits into 2 once it reaches a certain size
Responses: Cidia propels the cell forward
Homeostasis​: Collects and expels water to maintain a stable environment(osmoregulation)
Nutrition​: Englufs and digest food(heterotroph)
Reproduction​: Binary fission, sexual reproduction is possible
Excretion​: Diffuses through cell membrane(waste product)

Metabolism​: Catalysized by the enzymes in the cytoplasm
growth: Enlarges through photosynthesis produces organic molecules(glucose)
Responses: Uses eye spot tp sense light move towards light region(increases photosynthesis)
Homeostasis​: (osmoregulation) exorytosis with excess water from cytoplasm/vacuolses
Nutrition​: uses chlorplast to carry out photosynthsis
Reproduction​: Binary fission, sexual reproduction is possible
Excretion​: waste expelled via surface of plasma(exocytosis)

measured length of the scale bar (1mm = 1000um)/Actual size of scale bar (the number printed