B5 Growth and Development Summary
- Created by: Farhana
- Created on: 27-12-12 18:49
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- DNA
- A DNA molecule has 2 stands shaped in a DOUBLE HELIX
- Each strand is made up of nucleotides
- Nucleotides has 4 bases- Adenine, Cytosine, Guanine, Thymine (base pairing: A-T, C-G)
- Each set of 3 bases(triplet) codes for one amino acid
- Cells make proteins by joining amino acids together in a particular order
- Each set of 3 bases(triplet) codes for one amino acid
- Nucleotides has 4 bases- Adenine, Cytosine, Guanine, Thymine (base pairing: A-T, C-G)
- Each strand is made up of nucleotides
- Genes are sections of DNA that contains instruction for 1 particular protein
- Proteins are made by organelles called RIBOSOMES in the cytoplasm
- Cells make proteins by joining amino acids together in a particular order
- Proteins are made by organelles called RIBOSOMES in the cytoplasm
- DNA's found in the nucleus and can't move out because it's too big
- A copy of the DNA's made by a mRNA- shorter single strand of DNA to get copies to ribosome
- Proteins are made by organelles called RIBOSOMES in the cytoplasm
- Proteins are made by organelles called RIBOSOMES in the cytoplasm
- A copy of the DNA's made by a mRNA- shorter single strand of DNA to get copies to ribosome
- Chromosomes
- Nucleus
- Cell
- New cells are needed for GROWTH & REPAIR produced by MITOSIS
- Cells divide by MEIOSIS to produce gametes in 2 divisions
- MEIOSIS PRODUCES CELL WHICH HAVE HALF THE AMOUNT OF CHROMOSOMES
- Before cell divides, copies DNA. 1 arm of each chromosome clone of other arm
- 1st DIVISION: chromosome pairs line up in centre of cell
- Pairs pulled apart- each new cell has only 1 copy of each chromosome. Some of Dad's, some of Mum's in each new cell
- 2nd Division: chromosomes line up again in centre of cell- arms pulled apart
- Results in 4 gametes each w/ only a SINGLE set of chromosomes in
- 2nd Division: chromosomes line up again in centre of cell- arms pulled apart
- Pairs pulled apart- each new cell has only 1 copy of each chromosome. Some of Dad's, some of Mum's in each new cell
- 1st DIVISION: chromosome pairs line up in centre of cell
- Before cell divides, copies DNA. 1 arm of each chromosome clone of other arm
- MEIOSIS PRODUCES CELL WHICH HAVE HALF THE AMOUNT OF CHROMOSOMES
- Embryonic stem cells are undifferentiated up to the 8-cell stage
- Replaces ANY faulty cells in sick people
- Cloning used to make stem cells- nucleus of body cell into 'empty' egg cell
- Adult stem cells used to cure diseases extracting stem cells from bone marrow
- Adult stem cells used to cure diseases extracting stem cells from bone marrow
- Meristem tissues(in shoots & roots, where growing) contain stem cells
- Can divide and form organs for as long as plant lives
- Cuttings of meristems cells can produce clones with ROOTING powder to help it grow into complete plants
- Auxins are plant growth hormones (chemicals) that control growth near the tips of shoots & roots
- When a shoot has more light, more auxins move to shaded side =cells elongate faster on shaded side= grow towards light
- Phototropism is growth Towards or Away from light
- Positive phototropism: leaves, need light for photosynthesis= food. Grow towards light
- When a shoot has more light, more auxins move to shaded side =cells elongate faster on shaded side= grow towards light
- Phototropism is growth Towards or Away from light
- Positive phototropism: leaves, need light for photosynthesis= food. Grow towards light
- Negative phototropism: roots, need nutrients + water from soil for growth. Grow away from light down into soil
- Positive phototropism: leaves, need light for photosynthesis= food. Grow towards light
- Phototropism is growth Towards or Away from light
- When a shoot has more light, more auxins move to shaded side =cells elongate faster on shaded side= grow towards light
- Negative phototropism: roots, need nutrients + water from soil for growth. Grow away from light down into soil
- Positive phototropism: leaves, need light for photosynthesis= food. Grow towards light
- Phototropism is growth Towards or Away from light
- When a shoot has more light, more auxins move to shaded side =cells elongate faster on shaded side= grow towards light
- Cell
- First, the no. of organelles increase, then choromosomes are copied so cell has 2 copies of its DNA
- New cells are needed for GROWTH & REPAIR produced by MITOSIS
- Before cell divides, the DNA forms X-shaped chromosomes. Each 'arm' of a chromosome clones
- Chromosomes line up in the nucleus & cell fibres pull them apart to opposite ends
- Membranes form around each sets of chromosomes- nuclei of 2 new cells
- Lastly, cytoplasm divides & you have 2 new cells clone of parent cell- same DNA
- Membranes form around each sets of chromosomes- nuclei of 2 new cells
- Chromosomes line up in the nucleus & cell fibres pull them apart to opposite ends
- Gametes have 1 copy of each chromosome so when fertilised, zygote will have full set of 46
- Nucleus
- A DNA molecule has 2 stands shaped in a DOUBLE HELIX
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