Biology topic 3

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Name the 12 parts of a eukaryotic cell e.g animal cell.
Plasma(cell surface membrane),rough endoplasmic rectilium,nucleolus,centriole,nucleus,smooth endoplasmic rectilium,lysosome,ribosome,nuclear envelope,golgi apparatus,cytoplasm,mitochondrion
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E Describe the nucleus and its function.
Surrounded by a nuclear envelope,nuclear pores,contains chromatin which is made from DNA proteins,nucleolus.//Controls cell activities,transcription,proteins,ribosomes
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E Describe the lysosome and its function.
round organelle,surrounded by a membrane with no clear internal structure//contains digestive enzymes which digerst invading cells or break down worn out components of the cell.
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E Describe the ribosome and its function.
small organelle that floats freely or on the RER, made of proteins and RNA-not surrounded by a membrane//the site where proteins are made(protein synthesis)
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E Describe the rough endoplasmic rectilium and its function.
folds and processes proteins that have been made at the ribosomes.
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E Describe the smooth endoplasmic rectilium and its function.
no ribosomes, synthesises and processes lipids.
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E describe the golgi apparatus and its function.
fluid filled membrane bound, flattened sacs with transport and secretory vesicles//processes and packages new lipids and proteins and makes lysosomes.
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E describe the mitochondria and its function.
oval shaped with a double membrane, cristae form which are folds in the inner membrane, inside is a matrix.// the site of aerobic respiration where ATP is produced.
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E describe the centriole and its function.
small,hollow cylinders made of microtubules//involved in the separation of chromosomes during cell division.
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Describe the process of making a protein.1
mRNA is transcribed from DNA in the nucleus and is then transported to the RER. Here, ribosomes fold the polypeptide and are processed. The protein then enters the cisternae, where a vesicle breaks off and transports the protein to the golgi apparatu
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Describe the process of making a protein 2
s.The protein is modified and carbohydrates are added. A secretory vesicle then transports the protein to the cell membrane where it fuses and the protein is exocytosed out of the cell, or a transport vesicle transports the protein around the cell.
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Name the 10 parts of a prokaryotic cell e.g bacteria.
Cytoplasm,flagellum,circular DNA,Plasmids,Mesosomes,slime capsule,pili,cell wall,plasma membrane, ribosomes.
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P describe the cytoplasm and its function.
no membrane bound organelles, contains ribosomes which are smaller than eukaryotes.
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P describe the flagellum and its function.
long, hair-like structure which rotates for movement.
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P Describe circular DNA and its function.
one long coiled-up strand of DNA that floats freely and is not attached to any histone proteins.
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P describe plasmids and their function.
small loops of DNA that aren't part of the circular DNA, contain genes for antibiotic resistance and can be passed between prokaryotes.
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P describe mesosomes and their function.
inward folds in the plasma membrane
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P describe the slime capsule and its function.
protects bacteria from attack by cells of the immune system.
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P describe pili and their function.
help prokaryotes stick to other cells and can be used in the transfer of genetic material between cells.
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P describe the cell wall and its function.
supports the cell and prevents it from changing shape.
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P describe the plasma membrane and its function.
made of mainly lipids and controls the movement of substances into and out of the cell.
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what is the squamous epitheium
single layer of cells lining a surface.
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what is the ciliated epitelium
layer of cells covered in cilia on surfaces where thing need to be moved.
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what is the role of mitosis
growth, repair, asexual reproduction
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what is mitosis
a parent cell divides to produce 2 genetically identical daughter cells.
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what are the stages of the cell cycle
gap phase 1-cell grows and new organelles and proteins are made, synthesis-cell replicates DNA ready to divide by mitosis,Gap phase 2-cell keeps growing and proteins needed for cell division are made, Mitosis
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What is interphase
cell prepares to divide, DNA unravels and is replicated, organelles are replicated, ATP is increased
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What is prophase
chromosomes condense, centrioles move to opposite sides of the cell, forming a network of protein fibres called a spindle,nuclear envelope breaks down, chromosomes lie free in the cytoplasm.
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what is metaphase
chromosomes line up along the middle of the cell and become attached to the spindle by their centromere.
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what is anaphase
centromeres divide, separating each pair of sister chromatids, spindles contract, pulling chromatids to opposite poles of the spindle.
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what is telophase
chromatids reach opposite poles of the spindle. They uncoil and become long and thin again.A nuclear envelope forms around each group of chromosomes, so there are now two nuclei. cytokinesis occurs so 2 gi daughter cells are formed.
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Root tip squash
5mm tip of garlic/onion root, hydrochloric acid heated to 60'c, place root tip in hcl for 5 minutes, use a mounted needle to break open root, add acetic orcein as a stain to see chromosomes dividing,add a cover slip and carefully squash, microscope
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what is the mitotic index
number of cells with visible chromosomes divided by total number of cells observed.
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what is the structure of an egg cell
nucleus, cell membrane, follicle cells for a protective coating, zona pellucida-protective glycoprotein layer
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what is the structure of a sperm cell
nucleus,cell membrane,acrosome contains digestive enzymes to break down zona pellucida, flagellum for movement, mitochondria to provide energy.
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describe the process of fertilisation 1
sperm swims to egg cell, once it makes contact with the zona pellucida, the acrosome reaction occurs where digestive enzymes are released from the acrosome. these enzymes digest the zp,sperm head fuses with cell membrane of egg, triggers cortical rea
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describe the process of fertilisaton 2
ction where the egg releases cortical granules which thicken the zona pellucida to make it impenetrable to other sperm to prevent polyspermy,only the nucleus of the sperm enters the egg, the tail is discarded.
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describe meiosis
DNA replicates forming 2 identical copies called chromatids, DNA condenses to form 2sister chromatids, chromosomes rearrange by independent assortment into homologous pairs, homologous pairs are separated, sister chromatids are separated, 4 new dc,d
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what happens in meiosis to make cells genetically different
independent assortment where the chromosomes are randomly assigned other chromosomes, crossing over where chromatids twist around eachother, break and rejoin on the other chromatid.
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what genes are linked
genes are on the same chromosome, and are close together are less likely to be separated suring crossing over.
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what characteristics are sex linked
locus of the allele that codes for it is on a sex chromosome.
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what is totipotent
a stem cell that can differentiate into all cell types
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what is pluripotent
a stem cell that can differentiate into almost all cell types.
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describe the process of differential gene expression 1
All stem cells contain the same genes. when a chemical stimulus is present, some genes are activated, whereas others are inactivated. active genes are transcribed by mRNA and are then translated into proteins.they are modified and carbohydrates are a
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describe the process of differential gene expression 2
dded at the golgi apparatus. the proteins modify the cell and determine the cell structure and control cell processes. the cell is mow specialised.
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what is the lac operon
a cluster of genes
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what happens when lactose is present 1
the lactose binds to the repressor and changes its active site so it doesn't bind to the operator, so RNA polymerase can begin transcription forming gene x, permease which increases cell permeability and beta glactosidase which cleaves lactose into g
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what happens when lactose is present 2
lucose and galactose.
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what happens when lactose isn't present
the transcription factor binds to the operator, so RNA polymerase can't transcribe as it is blocked and can't bind to the promoter.
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what can stem cells be used for
spinal cord injuries-repair damaged nerve tissue, heart disease-replace damaged heart tissue
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what are the ethical issue of embryonic stem cells
potential life, no consent
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what are the guidelines for stem cell research
maximum age of embryo, codes of practice, licensed centres, information and advice for governments and professionals.
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what is continuous variation
a range of values, no distinct categories e.g height,mass,skin colour
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what is discontinuous variation
two or more distinct categories e.g blood group
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what is polygenic
a phenotype is influenced by genes aswell as the environment.
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what is DNA methylation
A methyl group is asdded to the CpG site which changes the structure of DNA so proteins and enzymes can't bind to the gene for transcription, so the gene is inactivated.
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what is histone modification
an acetyl group is added to the histone, which makes chromatin less condensed, so proteins in transcription can bind to DNA, activating genes. when removed, chromatin becomes highly condensed and genes are inactivated.
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what are epigenetic changes
changes above genes. they are passed down generations as cell division occurs.
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Other cards in this set

Card 2

Front

E Describe the nucleus and its function.

Back

Surrounded by a nuclear envelope,nuclear pores,contains chromatin which is made from DNA proteins,nucleolus.//Controls cell activities,transcription,proteins,ribosomes

Card 3

Front

E Describe the lysosome and its function.

Back

Preview of the front of card 3

Card 4

Front

E Describe the ribosome and its function.

Back

Preview of the front of card 4

Card 5

Front

E Describe the rough endoplasmic rectilium and its function.

Back

Preview of the front of card 5
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