Cells + Organelles Flashcards
What is an organism?
A living thing
What are some characteristics of a living thing?
reproductive capacity
growth
movement
metabolism
responsiveness
organised structure
death
Are viruses considered living?
Generally, no
What is a domain?
A level of classification above Kingdom
What are the three domains?
Archaea, bacteria and eukarya
Which two domains are the most similar?
Archaea and eukarya
What kingdoms are in Eukarya?
Plantae, animalia, fungi and protista
What is a prokaryote?
A celll lacking any membrane-bound organelles or a nucleus
What are all archaea and bacteria?
Prokaryotes
What is a eukaryote?
A cell with a membrane-bound nucleus and organelles
What is the size and complexity difference between eukaryotes and prokaryotes?
Eukaryotes are larger and more complex than prokaryotes
What are the three components of cell theory?
all organisms are made of one (unicellular) or more (multicellular) cells
new cells are formed by biogenesis (the division of pre-existing cells)
cells are the smallest organisational unit that a living thing can be
What is the difference between the plasma membrane of animal and archaea?
The archaea have uniquely structured membranes, able to maintain fluidity and permeability in extreme conditions. On the other hand, animalia membranes are selectively permeable but only in certain temperatures
Which cells have a cell wall?
all prokaryotes
fungi, plants and some protists
What are the cell walls of prokaryotes made of?
Murein: a mixture of proteins and carbohydrates
What are the cell walls of eukaryotes made of?
Mainly carbohydrates. Cellulose for plants. Chitin for fungi
Why have bacteria and archaea survived for so long?
Efficiency: Large SA:V ratio, so can replicate and metabolise quickly. All have a cell wall, offering extra protection. Can survive in a very diverse range of environments. Features that improve their resilience, such as flagella and pili
What are the features all cells have?
plasma membrane
cytoplasm
DNA (deoxyribose nucleic acid)
ribosomes
How many cells do prokaryotes have?
Unicellular
Do prokaryotes have chlorophyll sometimes?
Yes
What is the prokaryote’s form of genetic information storage?
A single circular DNA chromosome (nucleoid/nuclear region)
What genetic information storage do some prokaryotes have?
Plasmids: extra-chromosomal loops of double-stranded DNA
What are some add-ons that prokaryotes might have?
Pili, flagella, plasmids, polysaccharide capsule
What can prokaryotes be classified as: gram _ or _?
Postive or negative
What is gram negative?
When bacteria are stained with a ‘gram’ stain and don’t absorb it. AKA they have a second lipid membrane around their capsule
What are archaea?
Prokaryotes found in extreme conditions, such as high temperatures
What are the conditions that some archaea can survive in?
High temps
Low temps
Upper atosmophere
Very alkaline
No Light
Petroleum
Very acidic
Very salty
Little to no oxygen
Very arid
What are bacteria cell walls made of?
Peptidoglycan (murein)
What do many bacteria have surrounding them?
Cell capsule, for protection
What are pili?
Small hair-like projections
What do pili do in bacteria?
Can be used to transfer DNA between bacteria, assist movement and attach to surfaces
What are pili called if they attach to things?
Fimbriae
Do all bacteria have pili?
No, many do though
What are the three types of bacteria?
Photosynthetic:
use sun to make energy
Chemosynthetic: use energy made by chemical reactions
Heterotrophic: get energy through eating
Do all bacteria have flagella?
No, but many do.
What do bacteria use flagella for?
Movement/locomotion
What is different about archaea membranes?
They are adapted to withstand extreme conditions, so are a different structure
What are archaea cell walls made of?
A different type of peptidoglycan
Where do eukaryotic cells store their DNA?
In the nucleus, organised in linear chromosomes
What domain are protists?
Eukarya
Are protists diverse?
Very
How many cells do protists usually have?
One (unicellular) or they exist in cell colonies
What are protists mainly?
Heterotrophic, but some are also autotrophic (make food from raw materials and chemical reactions)
What does ‘motile’ mean?
Capable of motion
What allows protists to often be motile?
Cilia (in paracecium)
Flagella (in euglena)
Pseudopodia (in amoeba)
What domain is fungi?
Eukarya
What trophic are fungi?
Heterotrophic
How many cells do fungi have?
Multicellular, apart from yeast
What can fungi look like?
Plants, but they don’t have chlorophyll
What are fungi cell walls made of?
Chitin
Do fungi have cell walls?
Yes
What characterises fungi?
Masses of hyphae (filamentous growth used for vegetation growth)
Where do animal cells exist?
As a part of multicellular organisms with specialised cells of many types
Do animal cells have cell walls?
no
Are bacteria a domain or a kingdom?
Domain
What trophic are animalia?
heterotrophic
What is something that animalia can do?
Alter their shape for engulfment of foreign material
What is something that animalia sometimes have?
Flagella, allowing them to move
What is an example of animalia with a flagellum?
Spermatozoan
What is the cell wall of plants made out of?
Cellulose
In what way do plant cells exist?
As a part of multicellular organisms/plants with specialised cells of many different types
What are plants typically?
Autrotrophic, photosynthetic cells with chlorophyll
Example of fungi
mushrooms
example of protist
amoeba
what is the size of a prokaryotic cell
1-10um
What is the size of a plant cell?
30-50um
What is the size of an animal cell?
10-20um
Where are ribosomes in prokaryotes?
Scattered in cytoplasm
Where are ribosomes in eukaryotes?
Attached to rough endoplasmic reticulum or in cytoplasm
What does the plasma membrane do?
separate interior of the cell from the outside environment. controls what goes in and out. acts as boundary of cell
What is the cytoplasm?
Gel-like contents of the cell. Consists of cytosol (fluid component) and all organelles from the nuclear membrane to the plasma membrane
What occurs in the cytoplasm?
Many cellular activities
Where is the cytoplasm located?
Between the nuclear membrane and and plasma membrane
What is the purpose of the cytoplasm?
Suspend organelles and gives structure. Also increases surface area
What is dissolved in the cytosol?
Ions, salt, organic molecules, more than 80% water
What are ribosomes?
Organelles that make proteins
What is DNA?
genetic material that controls all activities in the cell. contains heridatory information
What do cells have in order to be efficient?
High SA:V ratio
How do organelles increase SA:V ratio
By having membranes
Why does having separate organelles help with?
Allowing different processes to occur at the same time with ideal conditions, increasing efficiency
What are the organelles shared by animal and plant cells?
Nucleus, cytoplasm, ribosomes, rough and smooth ER, golgi body, cell membrane, mitochondria, vacuole/vesicles, cytoskeleton
What do plant cells have that animal cells don’t?
Chloroplasts, cell walls and large vacuoles
Where do chemical reactions take place in the cell?
Cytosol
Which organelles have a double membrane?
Nucleus, mitochondia, chloroplasts
What is an effective way to transport matierals in and out of a cell?
Diffusion
What happens when cells become larger?
its sa:v ratio decreases. diffusion ceases to be an effectiven way to exchange materials with its environment
What is the controlling factor for cell size?
Effectiveness of diffusion
How do nutrients and wastes move across a cell surface?
Diffusion
What is the cell’s metabolism?
The chemical reactions that take place within a cell
What happens the SA:V ratio as the size of an object increase?
it decreases
What depends on the surface area?
The rate at whcih materials enter and leave the cell
What depends on volume?
The rate that materials are used or produced on the volume
Why is a high SA:V ratio important?
The surface area relates to how much material can enter a cell at one time. The volume relates to how much matieral is needed at one time, with the higher the volume, the more matieral needed to maintain it. A higher SA:V means more efficiency, improving the cell’s life. Larger cells have trouble exchanging materials at fast enough rates to sustain themselves