Topic 2 - Cells Flashcards
What are the components of the nucleus?
Nuclear pores - allow RNA to leave
Nuclear envelope - keep DNA contained
Chromatin - genetic information
Nucleolus - makes RNA
Nuclearplasm
What do centrioles do?
Make spindle fibres for cell division
What does the roughy endoplasmic reticulum do?
Site of protein synthesis, packages proteins into vesicles
What kind of ribosomes are present in animal cells and what do they do?
80s ribosomes - site of protein synthesis
What does the smooth endoplasmic reticulum do?
Makes and packages lipids and carbohydrates into vesicles
What does the Golgi apparatus do?
Modifies and packages molecules from SER and RER into either a secretory vesicles or a lysosome
What are lysosomes and secretory vesicles?
Lysosome - stores hydrolytic enzymes for phagocytosis
Secretory vesicles - fuses with cell membrane and releases contents (exocytosis)
What is the cell wall in a plant cell?
Made up of cellulose and pectin
Completely permeable
Prevents cell from bursting under osmotic pressure
What happens in the mitochondria?
Aerobic respiration
What does the large permanent vacuole in a plant cell do?
Stores water and pigment etc
Maintains turgidity
What are amyloplasts and chloroplasts?
Amyloplast - storage of starch
Chloroplast - site of photosynthesis
They can become each other
What are the components in a mitochondrion?
70s ribosomes
Plasmids
Matrix - contains enzymes for respiration
Outer membrane
Inner membrane - tightly folded into cristae to increase SA
Cristae - structure of inner membrane
What are the components of chloroplasts?
Starch grains - to become an amyloplast
Plasmid
70s ribosomes
Stroma (the chloroplasts cytoplasm)
Granum- stacked thylakoid membranes
Lamella - link granum together
What is the flagellum for in bacteria cells?
Locomotion and movement
What is the pila for in bacteria cells?
Enable interactions with host - for adherence to surfaces
What are the 2 types of DNA in bacteria cells?
Plasmid DNA - contains genes and help bacteria survive adverse conditions
Circular DNA - contains genetic information
What kind of ribosomes are in bacteria cells?
70s ribosomes
What is the mucilaginous slime capsule for in bacteria cells?
Protection and preventing desiccation and prevents phagocytosis
What is the capsid in viruses?
A protein coat
What is in the capsid in viruses?
Nucleic acid
Reverse transcriptase (only in retroviruses(with RNA))
What are attachment proteins in viruses for?
Identify and attach to host cells
What are the components of viruses?
Attachment proteins
Lipid envelope
Matrix proteins
Matrix
Capsid
Nucleic acid
Reverse transcriptase
How do DNA viruses replicate?
Attach to receptors on host cell
Inject Nucleic acid which then inserts into chromosomes
Ribosomes then make viral proteins which form new viruses
New viruses burst cell and spread
How do retroviruses replicate?
Attaches to host cell
Inserts Nucleic acid and reverse transcriptase which makes DNA copy of viral DNA
This is inserted into chromosomes
Proteins make viral proteins
New viruses burst cell and spread
What are the steps of binary fission?
All DNA is replicated
Circular DNA molecules attach to plasma membrane
Cell elongates to separate circular DNA
Cell cleaves in two identical daughter cells
What are the five stages of the cell cycle?
Gap 1
Synthesis - all 3 = interphase
Gap 2
Mitosis
Cytokinesis
What happens in gap 1 and 2 of mitosis
Protein synthesis
Cytoplasm grows
Energy stores increase
ATP synthesis
Organelles replicate
What happens in synthesis?
Semi conservative DNA replication
What are the 4 stages of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What happens in prophase?
Chromosomes condense and become shorter and thicker
Nucleolus and nuclear membrane break down
Centrioles move to opposite poles and form spindle fibres
What happens in metaphase?
Spindle fibres complete
Each centromere attaches to a spindle fibre from each pole
Chromosomes line up on equator
What happens in anaphase?
Spindle fibres contract and shorten
Centromeres split
Chromosomes split
Chromatids separate and are pulled to opposite poles centromere first
What happens in telophase?
Identical sister chromatids real poles and unwind to become chromosomes
New nuclear envelopes forms
What are the components of the cell membrane?
Phospholipid bilayer
Cholesterol
Intrinsic proteins
Extrinsic proteins
Glycolipids
Glycoproteins
What is the use of the phospholipid bilayer?
It is impermeable to most substances e.g. polar molecules (glucose and amino acids) and ions (are repelled by hydrophobic FA tails)
It is permeable to lipid soluble molecules and small uncharged molecules (O2 + CO2)
What is the use of cholesterol in the cell membrane?
Dissolved into FA tails
Helps stabilise membrane
Makes less fluid at higher temperatures
What intrinsic proteins do ions travel through?
Intrinsic channel proteins
Travel using facilitated diffusion
What intrinsic proteins do polar molecules travel through?
Intrinsic carrier proteins
Travel using facilitated diffusion
What are the uses of glycolipids glycoproteins and extrinsic proteins in cell membranes?
Cell markers (antigens)
Receptors
What does the cell membrane do?
Prevents substances passing through
Separates contents of cells
Allows certain substances through
Cell signalling
