Cell Structure Flashcards
Organelle
-A structure of a cell with a specialised function.
Seven life processes (7)
- Movement
- Respiration
- Sensitivity
- Nutrition
- Excretion
- Reproduction
- Growth
Division of labour
-When each organelle has a specific function
Cytoskeleton
-An internal framework of protein fibres that supports the shape of the cell and moves organelles within
Microtubules (4)
- 25nm in diameter
- Made of a protein called tubulin
- Used to move organisms through a liquid or waft a liquid past a cell (e.g. Moving chromosomes during mitosis or moving Golgi vesicles)
- These proteins are known as microtubule motors and use ATP
Flagella (undulipodia) and cilia
- Made up of a cylinder of 9 microtubule pairs with one pair in the centre
- Undulipodia are longer than cilia
- Microtubules use ATP to move
- Undulipodia exist in ones or twos on cells
- Cilia occur in large number
- Flagella are made of a spiral protein (flagellin) attached by a hook to a protein base
- Disk spins using ATP
Vesicles and vacuoles (3)
- Membrane bound sacs in a cell
- Used to carry substances around the body
- The vacuole in plant cells provides cell stability by pushing against the cell wall an making it turgid
Cell wall (3)
- Made of cellulose; a carbohydrate polymer made up of glucose
- Cellulose forms a sieve like network
- Supports the cell as it held rigid by the pressure from the vacuole
Nucleus (3)
- Consists of genetic material and proteins
- Holds instructions for protein synthesis
- Controls what enters and leaves the cell
Chromatin
-Dark patches condense into visible chromosomes during cell division
Rough endoplasmic reticulum
-Transports proteins that were made on the attached ribosomes
Smooth endoplasmic reticulum
-Makes lipids for use in cells (e.g. Cell membranes)
Golgi apparatus
- Receives proteins from the endoplasmic reticulum’s and modifies them
- Packaged and sent off to be transported in a vesicle
- Vesicles can be secreted out the cell
Mitochondrion (3)
- Where ATP is produced during aerobic respiration
- Inner membrane is tightly folded to form cristae
- Central part of mitochondrion is called the matrix
Chloroplasts (2)
- Site of photosynthesis in plants cells
- Light energy is used to initiate this reaction making carbohydrate molecules from water and carbon dioxide
Lysosomes (3)
- Contains powerful enzymes to break down materials
- E.g. White blood cell lysosomes break down foreign pathogens.
- Lysosomes in the head of a sperm breaks down the surrounding wall of an egg
Ribosome
- Not membrane bound
- Site of protein synthesis
The hormone production sequence (9)
- mRNA copy of the instructions are made
- mRNA leaves nucleus via a nuclear pore
- mRNA attaches to ribosome where it is read and assembled into a protein
- Hormone molecule is contained in a vesicle and travels to the Golgi apparatus
- Vesicle fuses with Golgi apparatus
- Golgi apparatus packages molecule for release
- Packaged molecule moves towards plasma membrane
- Vesicle fuses with plasma membrane
- Plasma membrane opens to release molecule
Eukaryotes (5)
- Cells that contain membrane bound organelles and have a true nucleus
- Genetic material held in a nucleus
- 15~25 micrometres in diameter
- Ribosomes are 22nm in diameter
- Cell wall is sometimes present
Prokaryotes and disease (3)
- Some prokaryotic cells are well known for causing disease and a few of those are resistant to antibiotics as well
- The resistance is coded on the plasmid so it can be passed onto other bacterial cells
- Researchers are looking for antibiotics that slow down the grown of bacterial cells while not harming the eukaryotic cells
Prokaryotic cells (10)
- Don’t contain membrane bound organelles
- Have a plasma membrane
- Have a cell wall made of peptidoglycan
- Have small ribosomes 10nm in diameter
- DNA is formed in a single loop called a circular chromosome
- Can have plasmids
- Has naked DNA
- ATP production occurs in the plasma membrane I mesosomes
- Some have flagella
- Diameter of cell is 0.5~5 micrometres
Examples of helpful prokaryotes (4)
- Making cheese and yoghurt (lactobacillus)
- In mammalian intestines, they help produce vitamin K and digestion
- Human skin is covered in a ‘normal flora’ o bacteria that prevents pathogens from getting into the body
- Sewage treatment
