Chromosome

• Chromosomes contain genes and colored bodies.
• Chromosomes have centromeres located in the middle and are used during cell division as an attachment point.
• Chromosomes have telomeres located at both ends and are used to maintain chromosomal integrity by capping off the ends.
• Chromosomes are classified into autosomes or sex chromosomes based on their centromere location.
• Autosomal chromosomes come in 22 pairs and are numbered from 1 to 22.
• Sex chromosomes come in a single pair, the 23rd pair, and are designated as X and Y.
• Chromosomes can have different centromere locations such as metacentric, submetacentric, acrocentric, and telocentric.
• Group C chromosomes are medium size and submetacentric, including chromosomes 6 through 12, X.
• Acrocentric chromosomes are hard to observe but still present.
• Group E chromosomes are medium size and acrocentric, including chromosomes 16 through [/flashcard>
• Stalk/Satellite chromosomes contain genes which code for rRNA and are responsible for nucleolus formation.
• Group A chromosomes are the largest and include chromosomes 1, 2, and 3, which are metacentric, submetacentric, and metacentric respectively.
• Group D chromosomes are medium size and acrocentric with satellites, including chromosomes 13 through 15.
• The centromere is located at the terminal end of the chromosome.
• Group B chromosomes are large and submetacentric with two arms of different sizes, chromosomes 4 and 5.
• Acrocentric chromosomes do not exist in humans.
• Metacentric chromosomes have two arms of roughly equal length.
• Submetacentric chromosomes have short and long arms of unequal length with the centromere more towards one end.
• Acrocentric chromosomes have a single arm that is very long compared to the other arm.
• Telocentric chromosomes have no arms at all.
• Reverse pattern of G bands is a characteristic of G-Banding.
• heterochromatin is a state where chromatin is tightly packed and gene density is low.
• Quinacrine stain results in a fluorescent pattern where dark bands represent A-T and light bands represent G-C.
• Heterochromatin is a state where chromatin is tightly packed and gene density is low.
• Nucleolar Organizing Region (NORs) are located on the short arms of the acrocentric chromosomes 13, 14, 15, 21 and 22.
• Lightly packed chromatin is a state where genes are enriched but not yet active.
• NOR Banding identifies genes for ribosomal RNA that were active in a previous cell cycle.
• G-Banding is a method used to identify genes that were active in a previous cell cycle.
• Active transcription is a state where genes are transcribed.
• Staining with Giemsa dye results in dark bands representing A-T and light bands representing G-C.
• C-Banding is a method used to identify genes that were active in a previous cell cycle.
• R-Banding is a method used to identify genes that were active in a previous cell cycle.
• C-Banding identifies genes for ribosomal RNA that were active in a previous cell cycle.
• NOR Banding is used to identifies genes for ribosomal RNA that were active in a previous cell cycle
• Euploidy is the condition of having a normal number of structurally normal chromosomes.
• Polyploidy is when the chromosome number is higher than 46 but is always an exact multiple of the haploid chromosome number of 23.
• Chromosomal banding is a staining technique for chromosomes that comprises alternating light and dark strides (bands) and appears along its length after being stained with a dye.
• Types of chromosomal banding include G-Banding, R-Banding, and Q-Banding.
• Group G includes chromosomes 21-22, Y which are small and acrocentric.
• Triploidy (3n) is an akarotype with 69 chromosomes.