1.2 - Cell Structure and Organisation Flashcards
What do eukaryotic cells contain?
Membrane bound organelles, which are enclosed in the cytoplasm. Most disguinshed one being the nucleus.
What form of measurement is used for cells and organelles?
Micrometres, um
What system is used for units?
Syteme Internationale
Name the 12 organelles within an animal cell.
- Nucleolus
- Nuclear pore
- Nuclear envelope
- Chromatin
- Rough endoplasmic recticulum
- Ribosomes
- Golgi apparatus
- Mitochondrion
- Lysosome
- Vesicle
- Centriole
- Plasma
Name the 16 organelles of a plant cell.
- Nucleolus
- Nucleus
- Nuclear pore
- Rough endoplasmic recticulum
- Smooth endoplasmic recticulum
- Ribosomes
- Golgi apparatus
- Mitochrondrion
- Tonoplast
- Vacuole
- Vesicle
- Chloroplast
- Cell membrane
- Cell wall
- Cytoplasm
- Plasmodesa
What is the size of the nucleus?
10-20 um
What is the function of the nucleus?
It contains DNA and proteins, which combine to make chromosomes, which direct protein synthesis as they are the site of transcription.
What is the structure of the nucleus? (5 features)
- 2 membranes
- first one being the nuclear envelope, passing large molecules like mRNA
- second one is the continuous endoplasmic recticulum
- nucleoplasm contains chromatin (coils of DNA with protein)
- a small spherical body called nucleolus which is site of formation for rRNA, ribosomes)
What is the size of mitochondrion?
Cylindrical and are 1-10nm in length
What is the function of mitochondia?
Produce ATP in aerobic respiration
What cells need more mitochondia?
Metabolically active cells (eg muscle)
How is the shape of mitochondria efficient?
The cylinder shape reduces diffusion distance between the edge and the centre, making aerobic respiration more efficient.
Where are chloroplasts found?
Found in photosynthesising tissue in plant cells
What are the function of chloroplasts?
Turns the suns radiation into chemical energy usable by organisms.
What is the endosymbiotic theory?
A theory in which suggests chloroplasts and ribosomes once existed as singular organisms, but over time have become a permanent feature needed in cells (‘symbiotic’)
What is the structure of the endoplasmic recticulum?
Parallel double membrane forming flattened sacs with interconnected, fluid filled spaces called cisternae.
What is the function of the endoplasmic recticulum?
Allows the transport of materials though a cell
What is the difference between RER and SER?
SER -lacks ribosomes, associated with the synthesis and transport of lipids.
RER - has ribosomes on the outer surface and transports proteins.
What are the size of ribosomes?
70s in pro, 80s in euk
Structure of ribsomes?
- one large and one small subunit
- made in nucleolus from rRNA and protein
Function of ribosomes?
Many, including protein synthesis and polypeptide production.
What process does a golgi apparatus go through?
Vesicles with polypetides pinch off and fuse with golgi body
The proteins are modified and packaged, and then at the other end, the vesicles are pinched off
What are the 5 functions of the golgi apparatus?
- acronym!
-produce enzymes
-secreting carbs
-producing glycoprotein
-transporting and storing lipids
-forms lysosomes
Every Cow Grazes Long Leaves
What are lysosomes?
Small, temporary vacuoles with a single membrane, formed when pinched off golgi apparatus
What can lysosomes contain?
Potentially harmful digestive enzymes, which are released when the cell needs to recycle worn out organelles
Location of centrioles?
Occur in all animal cells and most protocistans, and are located just outside the nucleus.
What is the structure of a centriole?
2 rings of microtubiules, making hollow cylinders positioned at right angles. Together they can be called a centrosome.
What is the link between centrioles and cell division?
They make the spindle
What is a vacuole?
All plants have large pearmenent vacuoles containing a fluid filled sac bounded by a single membrane (the tonoplast)
What does cell sap in a vacuole store?
Gluocose, amino acids and minerals
Function of a vacuole?
Supports soft plant tissues
What is the structure of the cell wall?
Cell walls in plants are held together in microfibrils, aggregated into fibres, embedded in a polysaccharide matrix called pectin
What are the 3 main purposes of a cell wall?
Transport - fully permeable to most molecules
Mechanical strength - makes the cell wall very strong
Communication - plasmodesmata can travel through the pores in the cell wall
Name the 7 stage process of interrelated organelles.
1) Nucleus contains chromosomes, DNA encodes proteins
2) Pores in envelope allow mRNA to attach to ribosomes in cytoplasm/RER
3) Ribosomes contain rRNA
4) Protein synthesis then occurs at ribosomes, producing primary proteins
5) Polypeptides move from ribosomes to RER and packaged into vesicles, which go to golgi body
6) Golgi body produces newly synthesised proteins
7) Phospholipids and triglycerides move through SER to various destinations in the cell
What is the definition of a prokaryote?
A single celled organism lacking membrane bound organelles, such as a nucleus with its DNA free in the cytoplasm.
What is an example of a prokaryote?
Bacteria
What is the definition of a eukaryote?
An organism containing cells that have membrane bound organelles, with the DNA in chromosomes within the nucleus.
What can be found on bacteria?
- cell membrane
- DNA
- mesosome
- ribosome
- cytoplasm
- cell wall
- slime coat in some bacteria
- plasmid
- flagellum
Why can viruses be described as acellular?
They are not made of cells.
What is the structure of a virus?
- Core of nucleic acid
- DNA or RNA
- protein coat (capsid)
- sometimes a membrane
What are bacteriophages?
Viruses that can attack bacteria
Name a common bacteriophage.
T2 which attacks E.coli.
Name some viruses in humans.
Flu, chicken pox, HIV
Name 2 viruses in plants.
Tobacco mosaic virus and cauliflower mosaic virus.
Name some viruses found in animals.
Swine flu, cow pox, feline leukamia virus.
What is differientation?
The development of a cell into a specific type.
What are tissues?
A group of cells working together with a common function, structure and origin in the embryo
What are the 3 tissue types found in mammals?
Epithelial, muscular and connective
What is epithelial tissue?
A continuous layer, covering internal and external surfaces, no blood vessels but may contain nerve endings, sits on a basement membrane.
What is the function of epithelial tissue?
Protective or secretory
Name the 3 types of epithelial cell.
Cuboidal, columnar and squamous
Where is cuboidal epithelium found?
Proximal convuluted tubule of kidney nephron and in salivary glands
What is a distinctive feature of a columnar epithelium?
Cilium for transport
Where is squamous epithelium found?
Forms the walls of the alveoli and lines the bowmans capsule.
What are the 3 types of muscle tissue?
Skeletal, smooth and cardiac
What is skeletal muscle tissue?
Attached to bones and gives powerful contractions but tires easily, voluntary striated muscle.
What is smooth tissue?
Individual spindle cells that contract rhythmically but with less power, involuntary muscle found in skin, unstriated muscle.
What is cardiac tissue?
Only found in the heart, contracts rhythmically although electrical pules can modify contractions, does not tire as long as there’s as impulse.
What is connective tissue?
- connects, supports or separates tissues and organs
- contains elastic and collagen fibres in extracellular fluid or matrix
- between the fibres there are fat storing cells (adipocytes) and cells of the immune system.
What is the definition of an organ system?
A group of tissues in a structural unit, working together and performing a specific function.
