Cells, genes and molecules Flashcards
What are the four fundamental molecular building blocks of all life?
- nucleic acids
- proteins
- lipids
- sugars
What form does DNA have?
double helix with two anti-parallel strands
How are DNA strands read?
they are directional and read from the 5’ end towards the 3’ end of the strand
What are the building blocks of proteins?
Amino acids
What two functional groups are present in the common structure of amino acids?
Carboxyl group and amino group
What causes the variation among different amino acids?
Differences in the R group in the side chain
How many types of amino acids are encoded in the genome and used to make proteins?
Twenty amino acids
how many possible codons are there?
64
How are codons read on mRNA?
from 5’ to 3’ in ribosomes
what are proteins used for?
- speed up metabolic reactions
- act as transporters
- provide structural support
- repair damage
How are amino acids organised?
they are organised into a polypaptide chain and then folded into a three dimensional structure
What are the main functions of lipids?
- to form membranes
- energy storage
- cell communication
What are the two main types of cells on the planet?
- prokaryotic
- eukaryotic
What defines a prokaryote?
a cell that has no nucleus (eg: bacteria and archaea
What defines a eukaryote?
larger and more complex cells with many membrane bound oranelles that perform specialised functions
What are common features of cells?
-have a membrane
- sense and respond to their environment
- contain DNA in the form of genes
- use common building blocks such as amino acids,
proteins, carbohydrates, lipids, nucleic acids
What is compartmentalisation?
the division of space inside a cell that allows different reactions to occur simulatnaously
What are the different types of RNA?
- mRNA (messenger RNA) that can be translated into protein
- tRNA (transfer RNA) and rRNA (ribosomal RNA) that are involved in protein synthesis
- miRNA (micro RNA) can regulate gene expression
what are non-coding regions of DNA called?
introns
What are coding regions of DNA called?
exons
What are regulatory regions and where are they found?
region that guides molecules such as transcription factors and RNA polymerase to the start of the gene at either end of coding regions
How is transcription stopped?
stop codon is read
how are non-coding areas removed from an RNA sequence to make mRNA?
they are spliced out
What does LECA stand for?
Last Eukaryote Common Ancestor
What organelles are believed to have been contained in LECA?
- Nucleus
- Mitochondria
- Golgi
- Lysosomes
- Cytoskeleton
From which domain did eukaryotic cells emerge?
Archaea
What is the endosymbiotic theory?
an Archaea cell formed a symbiotic relationship with a bacterial cell that became the mitochondria and later was repeated with a photosynthetic bacteria to create chloroplasts
What is the first identified phylum of Asgard archaea?
Lokiarchaeota
Where was Lokiarchaeota found?
In sediment around a deep-sea hydrothermal vent off the coast of Norway
What types of proteins do Asgard archaea contain genes for?
- Cytoskeletal proteins
- Proteins involved in vesicle trafficking
- Proteins involved in nuclear transport
What event allowed for the evolution of larger, more complex cells?
The emergence of the first eukaryote common ancestor (FECA) from the endosymbiosis of archaea and proteobacteria
What organelles did the last eukaryote common ancestor (LECA) likely have?
- Nucleus
- Cytoskeleton
- Golgi bodies
- Vesicles
- Multiple mitochondria
