2_LecVid Flashcards
• “Prenucleus”
PROKARYOTES
• Chromosomes are not contained within a membrane bound nucleus of the cell
Prokaryotes
Circular chromosome “______”
Nucleoid
•• “True nucleus”
EUKARYOTES
Chromosomes are located in the nucleus
EUKARYOTES
Linear chromosomes
Eukaryotes
Size
Pro
Eu
Unicellular
Multicellular
Nucleus
Pro
Eu
No true nucleus
DNA is suspended in the cytoplasm (nucleoid region)
Presence of nucleus
DNA
Pro
Eu
One circular DNA (plasmids)
Linear DNA
(coiled to form chromosomes)
Organelles
Pro
Eu
Absence of organelles
Presence of organelles
Examples
Pro
Eu
Bacteria and Archaea
Protists, Humans, Plants, Fungi
is a chemical which stores the genetic information of an organism
DNA
are encoded for different proteins
Genes
Determines many functions such as gene regulation
DNA
Determine the traits of an organism
Genes
A long chain polynucleotide
DNA
Small stretches of DNA
Gene
Not the only genetic material shared by organisms
DNA
Made up of either DNA or RNA
Genes
- coiled DNA strands to basic proteins called histone
Chromatin
Present in metabolically active cells
Chromatin
- Chromatin that has undergone further condensation
Chromosome
Present in actively dividing cells
Chromosome
2 types of chromatin:
Heterochromatin
Euchromatin
• dense clumps under light microscope
• Tightly coiled around histones
• Not used by the cell
Heterochromatin
• Less coiled portion of the chromosomes, finely granular material electron microscope and lightly stained basophilic areas
Euchromatin
•Contain the genetic material
Consists of DNA, proteins, and small amount of RNA
CHROMOSOMES
•Essential parts of chromosomes:
Telomeres
Origin of replication sites
Centromeres
• Tightly packaged DNA
• Found only during cell division
• DNA is not being us for macromolecule synthesis
Chromosomes
• Unwound DNA
• Found throughout
Interphase
• OVA is being used for macromolecule synthesis
Chromatin
•Chromosome consists of 2 parallel strands called
chromatids
•Chromosome tips
•Shorten with each mitotic cell division
TELOMERES
•Protects the chromosome during cell division from deterioration
TELOMERES
Telomeres contains______ sequence
TTAGGG
•Largest constriction of a chromosome
CENTROMERE
•Spindle fibers are attach when cell divides
DNA and protein
Centromere
MORPHOLOGIC TYPES OF CHROMOSOMES
MSAT
Metacentric
Submetacentric
Acrocentric
Telocentric
-If centromere is in the middle, and the arms are about of equal length
Metacentric
-If the centromere is between the midpoint and one end
Submetacentric
-If it is near one end
Acrocentric
- If it is at the end
Telocentric
Germ line (germ cells)
Haploid
23 chromosomes (n) in human
Somatic cells
Diploid
46 chromosomes (2n) in human
•Has two sets of chromosomes or 46 chromosomes
DIPLOID CELLS
DIPLOID CELLS
•Pair of chromosomes are
homologs
•Identical size, same banding pattern, and similar composition of genetic material
Diploid cells
•Displays chromosomes in pairs by size and physical landmarks that appear during mitotic phase
KARYOTYPE
23 human chromosomes are numbered from largest to smallest-1 to 22 and other two are the X and Y
Karyotype
KARYOTYPE
•The first 22 pair of chromosome are called
autosomes
•The last pair of chromosomes is called
sex chromosomes
(XX and XY)
A______ displays chromosome pairs in size order.
Note the extra chromosome 21 that causes______
karyotype
trisomy 21 Down syndrome
•Process by which the information encoded in a gene is used to direct the assembly of a protein molecule.
GENE EXPRESSION
Control of gene expression:
• Chromatin remodeling
• microRNAs
•Enzymes add or deleted in small organic chemical groups to histones
•Chromatin remodeling
•Three major types of small molecules that bind to histones:
-acetyl groups
-methyl groups
-phosphate groups
attracts the enzyme (acetylase) that adds acetyl groups to specific lysines on specific histones this promotes transcription
Enhanceosome
attracts the enzyme (acetylase) that adds acetyl groups to specific lysines on specific histones this promotes transcription
Enhanceosome
remove acetyl groups, which shuts off gene expression.
Deacetylases
remove acetyl groups, which shuts off gene expression.
Deacetylases
________allow transcription to begin. Once acetyl groups are added to particular amino acids in the tails of certain histones, the TATA box becomes accessible to transcription factors. H3 and H4 are histone types.
Acetylated histones
_ binds to a specific amino acid in a specific histone type, a protein is attracted that shuts the DNA off
Methyl group CH3
control gene expression by binding to cytosine
•Methyl groups
•noncoding RNAs
binds to initial control regions of a particular set of mRNAs
MicroRNAs
•when a microRNA binds a “target” mRNA, it prevents_____.
translation
has many targets, it effectively controls the expression of sets of genes at a time
microRNA
______opens to allow transcription factors to bind, whereas_____ bind to specific mRNAs, blocking their translation into protein.
Chromatin
microNAs
