5004885
Description
Flashcards by Hannah Wislang, updated more than 1 year ago
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Created by Hannah Wislang
over 8 years ago
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| Question | Answer |
| Nucleus structure | Is the most prominent organelle 5-10mircometres in diametre. One nucleus in each cell usually, contains most but not all of the cells genes |
| Nucleus function | Stores genetic information and if the cells control centre |
| Nucleus is surrounded by | A nuclear membrane, which is composed of two membranes, both of which are lipid bilayers |
| The inner surface of the nuclear membrane is lined by | Nuclear lamina |
| Nuclear lamina is composed of | Intermediate filaments, which help maintain the shape of the nucleus, and organise the packing of the DNA |
| What happens if lamina is defective | Hutchinson-Gilford Progeria syndrome, the nuclei have abnormal shapes and results in accelerated aging |
| Nuclear pore structure | Are flower looking structures that allow molecules to travel in and out of the nucleus |
| Nuclear pore function | Allows mRNA, rRNA an tRNA to travel out of the nucleus. Allows control signals, energy and materials such as nucleotides to move into the nucleus. The control signals tell genes to be turned off or on |
| The DNA helix is combined with.. | HIisone proteinsto form chromatin fibres, chromatin fibres undergo multi level packing |
| The helix interacts with.. | Speicfic histone proteins H2-H4 to form a 10mirco metre diametre each bead is called a nucleosome |
| Further interactions between the DNA and .. | Histone 1 cause the 10nm fibre to coil into the 30nm fibre. The 30nm fibre loops to form 300nm fibre. |
| During cell divison the 300nm fibres... | Coil to form metaphase chromosomes |
| During metaphase some regions of chromatin are ... | More compact than others |
| Euchromatin | Is less dense and often genetically active |
| Heterchromatin | Is more dense and genetically inactive |
| Relationship between heterochromatin and Euchromatin | Is dynamic relationship |
| Location of the chromosome | Is not random |
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