Cells - Cell Structure Flashcards
What are the 5 kingdoms that every organism can be classified into?
- Prokaryotes
- Protoctista
- Fungi
- Plantae
- Animalia
What are the features of Monera?
- Cell type: Prokaryotic
- Organisation: Unicellular
- Nutrition: Miscellaneous
- Reproduction: Asexual by binary fission or budding
What are the features of Protoctista?
- Cell type: Eukaryotic
- Organisation: Unicellular, Filamentous or Multicellular
- Nutrition: Miscellaneous
- Reproduction: Mostly asexual by mitosis but can be sexual (meiosis)
What are the features of Fungi?
- Cell type: Eukaryotic
- Organisation: Multicellular
- Nutrition: Mostly saprotrophic
- Reproduction: Both sexually and asexually
What are the features of Plantae?
- Cell type: Eukaryotic
- Organisation: Multicellular
- Nutrition: Photosynthetic autotrophs
- Reproduction: Alternation of generations: sexual and asexual
What are the features of Animalia?
- Cell type: Eukaryotic
- Organisation: Multicellular
- Nutrition: Heterotrophs
- Reproduction: Mostly sexual with haploid gametes
What are the features and characteristics of the Nucleus?
- Contains chromosomes
- Controls cells activities by controlling transcription of DNA
- Nucleolus manufactures ribosomal RNA and assembles ribosomes
- Nuclear pores allow movement of RNA out to cytoplasm
What are the features and characteristics of the Rough Endoplasmic Reticulum?
- Ribosomes translate mRNA for protein synthesis
- Rough ER folds and processes proteins
What are the features and characteristics of Ribosomes?
- One large and one small subunit
- Found in cytoplasm and RER
- 80S found in eukaryotic cells ( ≈ 25nm diameter)
- 70S found in prokaryotic cells, mitochondria and chloroplast (slightly smaller)
- Made of rRNA and protein
What are the features and characteristics of the Smooth Endoplasmic Reticulum?
- Synthesises, process and transports lipids
What are the features and characteristics of the Golgi apparatus?
- Processes, modifies and packages lipids and proteins
- Vesicles often seen at the edges used to transport proteins to cell membrane
- Makes lysosomes
What are the features and characteristics of Lysosomes?
- Contains digestive enzymes called lysozymes
- Can be used to digest invading cells or break down worn out components of the cell
- Break down cells after they have died (autolysis)
What are the features and characteristics of Mitochondria?
- Site of aerobic respiration, forms ATP from respiratory substrates
- Double membrane, inner membrane forms cristae
- Matrix contains enzymes required for respiration
- Contains it’s own DNA and ribosomes
What are the features and characteristics of the Cell wall?
- Mechanical strength preventing bursting by osmotic pressure
- Allows water to pass along it and through the plant
- Pores within the walls “plasmodesmata” allowing exchange and transport of substances between 2 cells
What are the cell walls made of in different organisms?
- Plant cell: Cellulose
- Algae: Cellulose/Glycoprotein
- Fungal cell: Chitin
What are the features and characteristics of Chloroplasts?
- Site of photosynthesis
- Double membrane
- Stroma contains enzymes, ribosomes and DNA
What are the features and characteristics of the Vacuole?
- Fluid filled sac bound by a single membrane (tonoplast)
- Support plants by making them turgid
- Sugar/amino acids are temporary food store
What is the process of Protein Trafficking?
- Transcription of DNA and mRNA
- mRNA leaves nucleus
- Protein made on ribosomes enter rough ER
- Protein moves through the ER assuming three-dimensional shape en route
- Vesicles pinched off the rough ER contain the protein
- Vesicles from rough ER fuse to form the flattened sacs of the Golgi apparatus
- Proteins are modified within the Golgi apparatus
- Vesicles pinched off the Golgi apparatus contain the modified protein
- Vesicle fuses with cell surface membrane releasing protein
What is Cell specialisation?
- Multicellular organisms contain a wide range of different cells. Every cell is specialised to perform its function
- Cells may have different shapes, contents or numbers of an organelle
What are Tissues?
- A collection of similar cells that perform a specific function from one origin
What are Organs?
- Multiple tissues that are coordinated to perform a variety of functions, although they have one predominant major function
What are Organ Systems?
- Organs that work together as a single unit forming an organ system
- E.g. digestive / respiratory / circulatory
What are the general differences between Prokaryotic and Eukaryotic cells?
- DNA
- Lack of membrane bound organelles
- 70S ribosomes
- Some bacteria also have plasmids, capsules and flagellum
What are the differences between Eukaryotic and Prokaryotic DNA?
Eukaryotic:
- Longer
- DNA associated with histones
- DNA is linear
Prokaryotic:
- Shorter
- No histones
- DNA is circular
