Unit 1.1 DNA structure Flashcards
Provide the function of the cell wall?
Provides structure and support to the cell.
Provide the function of the plasma membrane?
Controls which Ions can enter or exit the cell. (described as selectively permeable)
Provide the function of the cytoplasm?
Is the site of most of the cell’s chemical reactions.
Provide the function of the vacuole?
Membrane-bound organelles, that contain the saps and sugars needed by the cell.
Provide the function of the chloroplasts?
The sites of photosynthesis, containing the green pigment chlorophyll.
Provide the function of the mitochondria?
The site of aerobic respiration. (double membrane)
Provide the function of the nucleus?
Contains the cell’s genetic information, and is a membrane-bound organelle that Controls the cell’s activities.
Provide the function of the ribosomes?
Sites of protein synthesis. Does not have a membrane. Made out of protein and rRNA molecules.
Provide the function of the smooth endoplasmic reticulum?
a network of membranes inside a cell, through which proteins and other molecules are free to move.
Provide the function of the golgi apparatus?
Helps to process and package proteins and lipid molecules, in particular the proteins that are being exported from the cell.
Provide the function of the vesicles?
transport materials between membrane compartments.
Provide the function of the rough endoplasmic reticulum?
has ribosomes on its surface.
What is a DNA nucleotide and what does it consist of chemically?
A single basic repeating unit of DNA, consisting of a deoxyribose sugar (5 carbons) and phosphate group backbone, and one of four complementary bases.
DNA nucleotides are joined together by _____________?
Strong covalent bonds
What is meant by the term complementary base pairing?
Complementary base pairing refers to the weak hydrogen bonds formed between adenine and thymine or guanine and cytosine in a DNA molecule. Bases being complementary means that they can only bind to their specific complementary partner.
What is meant by the term anti-parallel in relation to a DNA molecule?
This means that each strand in the DNA runs in an opposite direction, one strand runs in the 5’ to 3’ direction. Where the opposite stand will run in a 3’ to 5’ direction.
State the structure of a DNA molecule?
Double-stranded helix.
Where do cells store their genetic information? (within the DNA molecule itself)
In the sequence of bases of the DNA molecule.
In a Deoxyribose sugar molecule within the nucleotide, where do the other chemical components lie?
The phosphate group lies on the 5’ end of the deoxyribose, the base lies on the 1’ end, and at the 3’ end of the deoxyribose the nucleotide will bond to another nucleotide by strong covalent bonds.
What chemical bond holds two stands of DNA together?
Weak hydrogen bonds.
Name the two types of cells?
Prokaryotes and Eukaryotes.
What are the defining characteristics of a Prokaryote cell?
Prokaryotes are organisms that do not contain a true membrane-bound nucleus. Prokaryotes store their genetic information in large circular chromosomes. Prokaryotes may also contain circular rings of DNA called plasmids.
What are the roles of the plasmids?
plasmids contain additional genes, that can be used to the advantage of the organism for instance to provide antibiotic resistance, increasing the chances of the organism’s survival.
What are the defining characteristics of Eukaryotes?
Eukaryotes are organisms that contain a membrane bound nucleus. Eukaryotes also contain linear chromosomes that are tightly packaged around proteins.
What are the proteins that linear chromosomes in Eukaryotes tightly package themselves around
Histone proteins.
What makes Yeast a special Eukaryote?
Whilst Yeast contains a nucleus, and linear chromosomes wrapped around histone proteins, yeast also contains circular rings of DNA called plasmids.
Can circular chromosomes be found in Eukaryotic cells explain your answer?
Yes Eukaryotes contain circular chromosomes: This is because circular chromosomes can also be found in the mitochondria and the chloroplasts (it is thought that these circular chromosomes within Eukaryotes were incorporated from early bacteria or eukaryotes).
