Cells, Genetics And Inheritance Flashcards
(28 cards)
Describe the plasma membrane
Phospholipid bilayer with proteins, sugars and cholesterol present within it. Hydrophilic head, hydrophobic tail.
Name the contents of the nucleus
Nuclear envelope
Nucleolus
Chromatin
What are the functions of the plasma membrane proteins?
Immunological identity thanks to branched carbohydrate molecules. Act as receptors. Some are enzymes. Channel proteins. Active pumps.
What are tight junctions? Give an example
Impermeable junctions that bind cells together into leakproof sheets that prevent substances from passing through the extra cellular space between cells.
In the small intestine they prevent digestive enzymes from seeping into bloodstream.
What are desmosomes?
Anchoring junctions that prevent cells subjected to mechanical stress from being pulled apart.
What are gap junctions?
Function mainly to allow communication. The neighbouring cells are connected by connexons, which are hollow cylinders composed of proteins that span the entires width of the abutting membranes.
Name the organelles inside the cytoplasm
Mitochondria Ribosomes Endoplasmic reticulum Golgi apparatus Lysosomes Peroxisomes Cytoskeleton Centrioles Cillia/flagella
Name passive transport processes
Diffusion
Osmosis
Facilitated diffusion
Filtration
Which way do the molecules move in passive transport?
Area of high concentration to area of low concentration
Which way do molecules move in active transport?
Area of low concentration to area of high concentration
How is genetic material stored in a cell which is not dividing?
Chromatin
What is chromatin made of?
Deoxyribonucleic acid
Sugar phosphate backbone
4 bases- adenine, thymine, cytosine and guanine
Name the stages of mitosis in order
Prophase
Metaphase
Anaphase
Telophase
Name the stages of interphase
G1
S
G2
What happens in first gap phase (G1)?
Cell grows
What happens in S phase?
Chromosomes replicate
What happens in gap phase 2 (G2)?
Enzymes and other proteins needed for cell division are synthesised, by the end of G2, centriole replication is complete.
Name the 3 types of RNA
tRNA
rRNA
mRNA
Summarise transcription
Information transferred from DNA to mRNA
3 base DNA sequence is called a triplet, it corresponds to a codon on the mRNA.
What happens in translation?
Base sequence is translated into amino acid sequence
Where does translation occur?
Cytoplasm
What are recombinant chromosomes?
Chromosomes that have mixed contributions from each parent.
What is a karyotype?
Normal number of chromosomes for a species
What is a genome?
Complete set of chromosomes
