Topic 1: The Natural And Variety Of Living Organisms Flashcards
Name the 8 Functions of living orgamisms.
· Movement
· Reproduction
· Sensitivity
· Control
· Growth
· Respiration
· Excretion
· Nutrition
Movement
Can change position
Reproduction
can have offspring either sexually or asexually
Sensitivity
can detect stimuli, such as light, and then respond to them
Control
Can control their internal environment (homeostasis)
Growth
Can increase mass
Respiration
Can produce energy either aerobically or anaerobically
Excretion
Can remove toxic or waste produced by reactions in the body
Nutrition
Can absorb nutrients in order to use them for growth and repair
Eukaryotes
Eukaryotes are organisms that have a nucleus and organelles that are found within a plasma membrane
Nucleus
· Subcellular structure found in plant and animal cells
· Contains the genetic material, which codes for a particular protein
· Enclosed in a nuclear membrane
Cytoplasm
· Subcellular structure found in plant and animal cells
· Liquid substance in which chemical reactions occur
· Contains enzymes (biological catalysts, i.e. proteins that speed up the rate of reaction)
· Organelles are found in it
Cell membrane
· Subcellular structure found in plant and animal cells
· contain receptor molecules to identify and selectively control what enters and leaves the cell
Mitochondria
· Subcellular structure found in plant and animal cells
· Where aerobic respiration reactions occur, providing energy for the cell
Ribosomes
· Subcellular structure found in plant and animal cells
· Where protein synthesis occurs
· Found on a structure called the rough endoplasmic reticulum
Plants
· E.g. cereals (such as maize) or herbaceous legume (such as peas)
· Multicellular organisms
· Cells contain chloroplasts which is the site of photosynthesis: chlorophyll pigments within the chloroplast structure absorb light from the sun
· Cellulose cell walls which provide strength to the cell
· Contain a permanent vacuole, which stores cell sap and improves the cell’s rigidity
· Stores carbohydrates as starch or sucrose
What does a Plant cell contain?
· Cell wall
· Cell membrane (inside cell wall)
· Vacuole
· Cytoplasm
· nucleus
· Mitochondria
· Chloroplast
Animals
· E.g. mammals (such as humans) and insects (such as flies)
· Multicellular
· Cannot photosynthesise
· Do not have cell walls
· Have nervous systems in order to coordinate movement
· Store carbohydrates as glycogen
What does a animal cell contain?
· Cell membrane
· Mitochondria
· Cytoplasm
· Nucleus
Fungi
· Body is usually organised into a mycelium of thread-like structures called hyphae which have many nuclei but some are single-celled
· E.g. mucor has typical hyphal structure, yeast is single-celled
· Cell walls are made of chitin
· Feed by extracellular secretion of digestive enzymes which break it down into smaller pieces, which can then be absorbed (saprotrophic nutrition)
· May store carbohydrates as glycogen
Protoctists
· Single-celled organisms
· Some have features like animals cells, such as Amoeba, that live in pnd water
· Others are more like plants and have chloroplasts, such as Chlorella
Prokaryotes
Prokaryotes do not have a nucleus or membrane-bound organelles
Bacteria
· E.g. lactobacillus bulgaris (rod-shaped bacterium used to make yoghurt), pneumococcus (spherical bacterium that causes pneumonia)
· Single-celled and very small
· Have a cell wall, cell membrane, cytoplasm and plasmids
· Lack a nucleus but have circular chromosomes of DNA
· Some can carry out photosynthesis but they mainly eat off of other organisms, either dead or alive
Pathogens
Pathogens are disease-causing organisms and can be fungi, bacteria, protoctists or viruses
Viruses in Pathogens
· E.g. tobacco mosaic virus which prevents chloroplast formation, influenza virus, HIV virus leading to AIDS
· Viruses are smll particles (much smaller than bacteria) - not living organisms
· Parasitic
· can only reproduce within living cells
· can infect every typle of living organisms
· hijacks the cell mechanisms to create millions of copies of itself and then spreads within the host by cell bursting
· They come in a wide variety of shapes and sizes
· Do not have a cellular structure but have one type of nucleic acid (either DNA or RNA) and a protein coat
Bacteria in pathogens
· E.g. Salmonella (food poisoning)
· Can reproduce many times through binary fission
· Produce toxins that can damage cells
Protists in pathogens
· E.g. malaria
· Parasitic - use animals as their hosts to live in
Fungi in pathogens
· E.g. athlete’s foot
· Produce spored that can spread in the wind or between people
· Can treat wth fungicides
Amoeba
Protoctists that live in pond water and resemble animal cells
Cell
The basic building block of all living organisms
Cell membrane
A partially permeable barrier that surrounds the cell
Cell wall
An outer, structural layer that surrounds some cells. In plant cells, it is made of cellulose. In fungi, it is made of chitin
Chlorella
A protoctist that has features similar to plant cells e.g. chloroplasts
Chloroplast
An organelle which is the site of photosynthesis
DNA
A double-stranded polymer wound to form a bouble helix. It carries the genetic code
Eukarotic cell
A type of cell found in plants and animals that contains a nucleus
Human Immunodeficiency Virus (HIV)
An infectious virus that weakens the immune system and can lead to AIDS (acquired immunodeiciency syndrome)
Hyphae
Long filaments of a fungus that contain many nuclei
Influenza virus
An infiction virus that causes influenza (the flu)
Lactobacillus bulgaricus
A rod-shaped species of bacterium used to produce yoghurt from milk
Mucor
A multicellular fungus that has a hyphal structure
Mycelium
A collection of thread-like hyphae in a fungus
Pathogens
Microorganisms that cause infectious disease
Photosynthesis
An endothermic reaction in which energy is transferred from the environment to the chloroplasts by light
Plasmids
Loops of DNA found in the cytoplasm of prokaryotic cells
Plasmodium
Pathogenic protoctists that cause malaria
Pneumococcus
A spherical, pathogenic bacterium that causes pneumonia
Prokaryotic cell
A type of cell found in bacteria that does not cntain a nucleus
Protoctists
Microscopic single-celled organisms
Saprotrophic nutrition
The mode of extracellular nutrition in which digestive enzymes are secreted onto the food outside the cell and the products of digestion are absorbed
Tobacco Mosaic Virus (TMV)
A widespread plant pathogen affecting many species of plants which produces a mosaic pattern in the leaves. It infects chloroplasts and limits plant growth
Virus
A non-living organism that can only reprodce inside host cells. Viruses have no cells, but possess a protein coat containing nucleic acids(DNA or RNA)
Yeast
A single-celled fungus
