A-Level Biology

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  • Created by: 17Ritika
  • Created on: 10-03-19 13:32
What is an Animal Cell made of?
Organelles - Nucleus, ER, Golgi body, Lysosomes, Mitochondria, Ribosomes. They have a cytoplasm and a cell membrane.
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Structure of a Nucleus
DNA is wrapped around histones to form Chromatin. Nucleus had a double membrane, called a Nuclear Envelope, which contains pores. The Nucleolus produces a copy of mRNA. There is the Nucleoplasm containing DNA/Chromatin
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Endoplasmic Reticulum
RER- There are ribosomes, to make proteins. SER - There are no ribosomes, producing lipids/carbohydrates.
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Golgi Body
Produces Vesicles, modifying and packaging proteins. Proteins are packaged into vesicles for transport. Digestive enzymes are placed into lysosomes.(Vesicles that have a double membrane)
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Mitochondria
The site of respiration, releases energy, produces ATP. Has a double membrane, the inner membrane is folded into the Cristae (increases surface area for enzymes of respiration.The middle portion is called the Matrix
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Ribsomes
Made up of proteins and RNA. They area attached to RER and it the site of protein synthesis.
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What a Plant Cell made out of?
Organelles - Nucleus, ER, Golgi Body, Lysosomes, Mitochondria, Chloroplast Vacolue and Ribosomes. They also have a cytoplasm, cell membrane and a cell wall
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Structure of Chloroplast
Organelle is for photosynthesis and has a discs called thylakoids containing chlorophyll, stacked are called granum. It's surronded by a fluid called stroma and this organelle has a double membrane around it.
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What is Bacteria made out of?
DNA are in single loops and plasmids. Only have smaller ribosomes and mesosomes, in folding of cell membrane for respiration. Cell membrane and cell wall, murein, may have a capsule,water loss, and flagella,movement. There is also cytoplasm
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What is Virus made of?
DNA or RNA, if RNA has reverse transcriptase to turn RNA into DNA. There is also a protein coat called capsid and lipid coat. Attachment proteins are on the outside, which infects host cells by injecting DNA to make the vrius components
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Attachment Proteins
Attachment proteins are on the outside, which infects host cells by injecting DNA to make the virus components and uses the cell membrane to make the lipid coat, hence producing copies of the virus and destroying the host cell.
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What is a Chromosome
DNA is coiled and is formed during interphase of cell division in animals/plants, this is made out of two identical/sister chromatids joined by a centremere. Carries 2 copies of the same DNA molecule
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What is a Homologous Pair Of Chromosomes
A pair of chromosomes : 1 maternal strand and 1 paternal strand carries same genes but different alleles - there are 23 pairs in humans
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What is a Cell Division?
Formation of new cells in multicellular organisms, eukaryotes. Mitosis, produces genetically identical cells for growth and repair of tissues. Meiosis, produces genetically different haploid cells as gametes for sexual reproduction
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What does Mitosis produce?
2 genetically identical cells, diploid. (Have full set of chromosome/DNA)
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Benefit of Mitosis
Growth and repair of tissues
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Stages of Mitosis
Interphase/Mitosis/Cytokinesis
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Interphase
G1: Protein Synthesis S: DNA replication (double set of DNA) G2: Organelle synthesis
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Stages of Mitosis
Prophase/Metaphase/Anaphase/Telophase
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Prophase
Chromosomes condense and tiny bundles of protein called centrioles start moving to opposite ends of the cell to make a spindle. Nuclear envelope breaks down causing chromosomes to lie free in the cytoplasm
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Metaphase
Chromosomes line up along the middle of the cell and become attached spindle by their centrimore.
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Anaphase
Centromeres have divided and separate each pair of sister chromatids, Spindle contracts pulling chromatids to opposite poles - centre more first forming a v shape.
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Telophase
Chromatids now on opposite poles uncoil and become long and thin again - chromosomes. Nuclear envelope develops around each nuclei - cytoplasm via cytokineses.
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What happens to DNA mass in mitosis?
The mass halves
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What happens to chromosome number in mitosis?
Stays the same(diploid)
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What is Cancer
Formation of a tumour due to uncontrolled division of cells - uncontrollable mitosis
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How does uncontrolled cell division occur?
Due to mutations of DNA/cells forming cancer cells. Mutations can occur randomly or due to mutagens such as chemicals/radiation. Cancer cells are rapidly dividing cells, they spend less time in interphase and more time in other stages of mitosis
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Treatment for Cancer
Surgery/Chemotherapy/Radiotherapy
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Surgery
Aim of surgery is to remove the tumour
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Chemotherapy
Using drugs that inhibit mitosis in rapidly dividing cancer cells, a problem is also that they affect healthy cells causing side effects - hair loss. Treatment given as regular doses to allow time for normal healthy cells to recover in number
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Radiotherapy
Uses radiation to destroy cancer cells
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What does Meosis produce?
4 genetically different cells, haploid. (Half the number of chromosomes/DNA)
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Benefits of Meosis
Produces gametes which will all be used in sexual reproduction in animals and plants
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Meosis 1
Prophase 1, Metaphase 2, Anaphase 3,
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Other cards in this set

Card 2

Front

Structure of a Nucleus

Back

DNA is wrapped around histones to form Chromatin. Nucleus had a double membrane, called a Nuclear Envelope, which contains pores. The Nucleolus produces a copy of mRNA. There is the Nucleoplasm containing DNA/Chromatin

Card 3

Front

Endoplasmic Reticulum

Back

Preview of the front of card 3

Card 4

Front

Golgi Body

Back

Preview of the front of card 4

Card 5

Front

Mitochondria

Back

Preview of the front of card 5
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