cell biology Flashcards
what can organisms be?
they can either be prokaryotes or eukaryotes
prokaryotes and eukaryotes
which one is simple and which one is complex?
eukaryotic cells are complex and include;
- animal
- plant
- fungi
- protoctists
prokaryotes are simple and small
- bacteria
eukaryotes are organism made up of..
eukaryotes are organisms made up of eukaryotic cells.
prokaryotes is a
prokaryotes is a prokaryotic cell
(single celled organism )
what are animal cells made up of?
(5 things)
- nucleus
- mitochondria
- Ribosomes
-cytoplasm - cell membrane
what are plant cells made up of?
(8 things)
- cell wall of cellulose
- nucleus
- mitochondria
-cytoplasm
-cell membrane
-vacuole - ribosomes
- chloroplasts
what does the nucleus do?
the nucleus encloses genetic material
what does the cytoplasm do?
- cheimcal reactions take place
- watery sollution
what doe sthe cell memebrane do
- controls the molecules that can leave and enter the cell.
What is the role of the mitochondria?
Mitochondria are the site of aerobic respiration, so they release energy for the cell.
what does the ribosomes do
- sites of protein synthesis
- you need electron microscope to see
what does the chloroplasts do?
- they perform photosynthesis
- filled with chlorophyll
what does the cell wall do?
- strengthens the cell
- made from cellulose
what does a permanent vacuole contain and what does it do?
- contains cell sap
- helps give plant cells its shape
do plant cells or animal cells have a regular shape?
- plant cells have a regular shape
- animal cells can change their shape
what do bacteria have instead of a ‘true’ nucleus
- a single strand of DNA that floats freely in the cytoplasm
what are plasmids?
plasmids are rings of DNA
they are in bacteria cells and they usually have one or more
what are bacteria cells made up of?
(5 things)
- cell wall
- cell membrane
-plasmids - circular strand of DNA
-cytoplasm
what does bacteria live?
(3 things)
- skin
-body - every day objects in our environment
what do plasmids do?
they provide provide bacteria with genetic advatages such as antibiotic resistance
what does circular strands of DNA do?
- they hold all genes for that bacterium
what do microscopes allow us to do?
microscopes allow humans to see things that we cant see through the naked eye.
what do light microscopes allow us to see?
light microscopes allow us t see individual and large subcellular structures like nuclei.
what do electron microscopes allow us to do?
electron microscopes allow us to see smaller things in more detail like:
- mitochondria
- chloroplasts
- ribosomes
- plasmids
give one advantage of using a electron microscope over a light microscope
- higher resolution
- higher magnification
what is the formula for magnification?
magnification = image size/ real size
which of the following subcellular structures would you not expect to find in prokaryotic cell? choose one.
- plasmid
- nucleus
- cell wall
- cell membrane
- nucleus
give two differences in structure between a prokaryotic and eukaryotic cells.
- prokaryotic cells dont have a nucelus
- prokaryotic cells dont have a mitochondria
- eukaryotic cells dont have plasmids
- eukaryotic cells dont have a single circular strand of DNA
what is differentiation?
differentiation is the process by which a cell changes to become specialised for its job.
is the ability to differentiate lost at an early stage in plant cells or animal cells?
animal cells
how does differentiation happen?
as the cells change they develop different subcelluar structure and turns them into different types of cells which allows them to carry out specific functions.
what are five examples of specialised cells ?
- sperm
- nerve
- root hair
- muscle
- phloem and xylem
what is the function of a sperm cell and what is it specialisations?
function is for reproduction
- long tail and streamlined head for swimming
- lots of mitochondria for energy
- carry enzymes to digest through egg cell membrane
what is the function of a nerve cell and what is its specialisations?
function is for rapid signalling
- long to cover distance
- branched connections and the ends to connect to other nerve cells to create a network through the body.
what is the function of a muscle cell and what is its specialisations?
function is for quick contracting
- long so there is space to contract
- lots of mitochondria for energy to contract.
what is the function of a a root hair cell and what is its specialisations?
the function of root hair cells is absorbing water and minerals
- on the surface of plant roots
- gives the plant more surface areas so more minerals and water can be absorbed from soil
what s the function of phloem and xylem cells and what is its specialisations
the function of phloem and xylem is that they transport substances.
- transport substances like food and water around the plant
- to form tubes they are long and joined end to end
- xylem are hollow
- phloem have little subcellur structure so stuff can flow through.
what is a stem cells?
stem cells are differentiated cells
what can embryonic stem cells do?
they can differentiate into any type of cell ( all the cells a human needs)
- divide by mitosis
what can adult stem cells do?
- they can divide by mitosis
- they can only differentiate into different types of blood cells including:
- white
- red
- platelets
what can adult stem cells not do?
adult stem cells can replace damaged cells but they cant form new tissues like embryonic cells.
where can adult stem cells be found?
bone marrow - jelly like substance found in larger bones
What do we call the plant tissues that are continually growing and that contain stem cells?
meristems
where can meristems be found?
in areas of the plant that are continuously growing
(the tips of the roots and shoots)
what are 3 examples of cells that stem cells can differentiate in a plant?
- palisade cells (photosynthesis)
- phloem and xylem
- root hair cells
do plant stem cells exist for the plants entire life or do they disappear by the time the plant is fully developed?
plant stem cells stay for the plants entire life
name two different types of stem cells found in animals?
- embryonic stem cells
- adult stem cells
when a sperm cell ________ an egg they form a single cell called a ______
- fertilises
- zygote
are bacterial cells larger or smaller than animal cells
smaller
what are cells?
they are the smallest unit of life that can replicate independently
are animal and plant cells multicellular or are bacteria cells multicellular
animal and plant cells are multicellular
- bacteria are unicellular
what does unicellular mean?
each cell is its own organism
what are the five kingdoms of life?
- animals
- plants
- bacteria
- protoctists
- fungi
what are viruses not apart of the kingdoms of life?
they are not apart of the kingdom of life as they are not living organisms
which ones of these are multi cellular?
- animals
- plants
- fungi
- protoctists
- bacteria
- animals
- plants
- fungi (some are multicellular some are unicellular)
what are hetrotrophs
means that that organisms has to get energy from another organism
what are autrophs
an organism that can create energy from light,water,carbon dioxide
like plants when they get their energy from the sun.
are fungi hetrophs, autrophs or saprotrophs
fungi are hetroophs and saprotrophs
what is a saprotroph
saprotrophs are organisms that obtain their nutrients or engery through decaying or dead organic matter
(saprophytic nutrition)
what is saprophytic nutrition?
- organism secrets enzymes onto food outside its body
- wait fro enzymes to break down the food
- absorb nutrients back into the body
why can some fungi be considered as a pathogen
because theres a fungus that causes athletes foot
do protoctists have soemthing to do with humans?
most protoctists have nothing to do with humans however some can be considered pathogens. for example the species plasmodium can cause malaria.
are protoctists hetrotrophs autotrophs or saprotrophs?
hetrotrophs + autorophs
are animals hetrotrophs autotrophs or saprotrophs?
hetrotrophs
are plants hetrotrophs autotrophs or saprotrophs?
autotrophs
are plants hetrotrophs autotrophs or saprotrophs?
most are hetrotrophs but some can phtosythesis so they can be considered autotrophs.
what is the basic structure of a virus?
- protein coat - outside
- genetic material - inside
where can viruses reproduce?
- only reproduce inside living cells
- uses those cells to replicate
Which of the following are features of animals?
- reproduce sexually
- autotrophs
- unicellular
- reproduce asexually
- multi cellular
- hetrotrops
- reproduce sexually
- multi cellular
- hetrotrops
Which of the following are features of plants?
- autotrophs
- unicellular
- multicellular
- hetrotrophs
- sapotrophs
- autotrophs
- multicellular
Fungi can be unicellular or multicellular.
Is yeast unicellular or multicellular?
unicellular
Some fungi (for example mushrooms) have a body known as a mycelium, which is made up of loads of tiny thread like structures called _____
hyphae
What does the term ‘parasite’ mean?
An organism that depends on another organism to grow and reproduce
Which two of the following cells are adapted to their roles by having a large surface area?
- red blood cells
- nerve cells
- root hair cells
- xylem cells
- red blood cells
- root hair cells
what does multicellular mean?
an organism composed of many cells
Heart muscle tissue has to be able to beat continually without stopping. What adaptation would you expect heart cells to have?
A large number of mitochondria
multi cellular,eukaryotic cells require a ______ supply of new _______
multi cellular,eukaryotic cells require a continuous supply of new cells
chromosomes contain a large number of____
chromosomes contain a large number of genes
how many pairs of chromosomes does a human usually have?
23 pairs
body cells contain ___ of each ______
in other words they are ______
body cells contain two of each chromosomes
in other words they are paired
What do we commonly call the cells produced by mitosis?
daughter cells
When a cell divides by mitosis, how many cells are produced?
2
Are the cells created by mitosis genetically identical to each other, or genetically different?
genetically identical
Multicellular organisms, like ourselves, require a continuous supply of new cells.
What are the four reasons why new cells are required?
give examples of each of them
- asexual reproduction - to replicate copies of parent cells
- growth - more cells as we grow
- repair- replace the cells that we loose each day
- development - new cell types as tissues develop
what is an example of a cell that we need to replace by mitosis?
skin cells - they constantly fall of our bodies each day.’
what are chromosomes made of?
DNA
what ar eteh stages of teh cell cycle
1) the cell grows and the number o sub cellar structure like chromosomes increase
the DNA replicates to form two copies of each chromosome.
2 mitosis takes place and cell is divided - nucleus divides
3 the cytoplasm and cell membrane divided to create two identical daughter cells
what is mitosis?
the process in which a single cell turns into two identical daughter cells
what is the stages of mitosis?
one set of chromosomes ares pulled to each end of the cell and the nucleus divides
the cytoplasm and cell membrane divides to create two identical cells which are identical to the parent cell
what is the cell membrane?
the cell membrane is a protective barrier outside the cell
what is the cytoplasm
a jelly like substance that fills the cell
what is chlorophyll
a green pigment within chloroplasts that absorbs sunlight for photosynthesis.
it is chlorophyll that makes plants green
Which type of stem cell can only differentiate into different types of blood cells?
adult stem cells
What is the problem in type 1 diabetes?
The pancreas is damaged and no longer produces insulin
When nerve cells are damaged, messages can no longer be sent to the muscles properly. This can lead to the loss of the ability to move some or all of your body
What do we call this condition?
paralysis
Extract ________ stem cells from early embryos.
Grow them in a ____________
Stimulate them to ___________ into whichever type of ____________ cell that we want.
Give them to the patient to ________ their faulty cells.
Extract embryonic stem cells from early embryos.
Grow them in a laboratory.
Stimulate them to differentiate into whichever type of specialised cell that we want.
Give them to the patient to replace their faulty cells.
Give two drawbacks of using embryonic stems cells in stem cell therapy.
- the body immune could reject the cells as the embryo and patient have different genotypes
- embryos have a limited supply of stem cells
what are advantages of using adult stem cells instead of embryonic stem cells in stem cell treatment?
- the body wouldn’t reject them as their from the patients own body
- because their taken from the patient there isnt a limited supply
Is stem cell research in the UK legal or illegal?
Legal but scientists have to follow strict instructions
why are stem cells used in medicine?
to replace faulty cells
how can doctors prevent the body rejecting embryonic cells in stem cell treatment?
by giving the patent medication to suppress the immune system
- may not always work
- often causes side affects
The stem cells could be infected with a _______ whilst in the laboratory, which could then infect the patient.
As stem cells divide quickly, there is a chance they could divide uncontrollably once they’ve been transplanted, and then develop into a _______.
virus
tumor
what are the ethical reasons against the use of embryonic cells in stem cell treatment and the counter for it?
- have potential for life
- curing existing people is more important than the rights of an embryo
- usually unwanted from a fertility clinic so would be destroyed anyway?
-
what is diffusion?
diffusion is the net movement of particles from an area of high concentration to an area of low concentration
True or false? If molecules are left alone they’ll move around randomly.
true
- molecules have kinetic energy so there constantly moving around
In which of the following states can molecules diffuse?
solid
liquid
gas
liquid
gas
Cell membranes are said to be ‘partially permeable’. What does this mean?
only some molecules can pass through
Which molecules are able to diffuse into and out of cells?
- water
- amino acids
- glucose
List three factors that affect the rate of diffusion.
- concentration gradient - larger concentration - higher rate of diffusion
- temperature - higher temperature diffusion happen more quickly
- surface area - larger diffusion happens more quickly
Will a larger surface area increase or decrease the rate of diffusion?
increase
Why does a higher temperature increase the rate of diffusion?
Higher temperature means particles have more (kinetic) energy
So they move around faster
And can diffuse more quickly
true or false - is diffusion a passive process
true - diffusion is passive so no energy is being used up by the cell
what is osmosis?
osmosis is the net movement of molecules across a partially permeable membrane from a region of higher water concentration to a region of low concentration
True or false? Osmosis is a special form of diffusion.
true
In living organisms, the partially permeable membrane is usually the ___________
cell membrane
Osmosis is the movement of which molecules?
water
True or false? During osmosis, water moves against the concentration gradient.
false - osmosis moves down the concentration gradient
What would happen to red blood cells if they were placed in pure water?
(osmosis)
They would gain water and swell
he water concentration would be higher outside the cell (in the pure water) than inside the cell. This means that water would move down its concentration gradient into the cell, causing it to swell and possibly burst.
what is active transport?
active transport is the movement of molecules across a membrane from a area of low concentration to high concentration. this requires energy from respiration
Is active transport a passive or active process?
active
True or false? Active transport can only take place across a membrane.
true
Which process provides the energy required for active transport?
Respiration
Homeostasis
Translocation
Photosynthesis
Why can’t plants absorb mineral ions by diffusion?
Their concentration is higher in the cell than in the soil
Which cells in the plant are adapted to absorb mineral ions?
Palisade mesophyll cells
Root hair cells
Xylem cells
root hair cells
Other than mineral ions, which other molecule do root hair cells absorb?
water
where does cellular respiration happen
mitochondria
Give two examples of exchange surfaces in humans and describe their function.
Example 1 - Alveoli (or lungs)
Example 1 - Alveoli allow oxygen and carbon dioxide to diffuse in and out of the body/bloodstream
Example 2 - Villi (or small intestines)
Example 2 - Villi allow nutrients such as glucose, amino acids, mineral ions etc to be absorbed from the small intestines into the bloodstream
Which type of organism can rely on diffusion to exchange all of the nutrients and waste products it needs?
bacteria
a cube is 4 cm x 4 cm x 4 cm
What is the total surface area of the cube?
Calculate the volume of the cube.
Calculate the surface area : volume ratio of the cube.
96
64
3:2
Which organisms have a larger surface area to volume ratio?
smaller organisms
What is an exchange surface?
A part of an organism over which substances are exchanged with the environment
Where are alveoli found?
the lungs
Root hair cells absorb _____ and______ ions from the soil.
water and minerals
State and explain three features that most exchange surfaces have in common.
- a large surface area so more molecules can be diffused at one time
- a thin surface so molecules only have to diffuse a short distance
- surface is permeable so substances are able to pass through
-Good supply of ‘external medium’
-Maintains a strong concentration gradient as the air or food etc is constantly replaced
State and explain three features of alveoli that make them good exchange surfaces.
- a large surface area so more molecules can be diffused at one time
- a thin surface so molecules only have to diffuse a short distance
- the surface is permeable so oxygen and carbon dioxide and diffuse across
Which adaptation in plants contributes to the efficient exchange of gases?
The flattened shape of their leaves
If you place a human hair on a microscope slide, and look at it under a microscope, is the hair itself considered the object or the image?
object
The hair itself is the object because it’s the real hair sitting on the slide.
If you look at cheek cells under a microscope, are the shapes that you see when looking down the microscope the object or the image?
image
The shapes you see are the image because they are a magnified version of the real object, created by the microscope.
What is the definition of magnification?
how many times larger the image is than the object
What is the pathway of light through a microscope?
Light source ➔ _____ ➔ microscope slide ➔ ______ ➔ _________ lens ➔ body tube ➔ _________ lens ➔ eye
Light source ➔ stage ➔ microscope slide ➔ object ➔ objective lens ➔ body tube ➔ eyepiece lens ➔ eye
Which type of microscope should be used to study sub-cellular structures (organelles)?
electron microscope
Which type of microscope is easier to use and which is cheaper?
light
electron
light
Convert 3 mm to μm.
3000μm
Convert 560 nm to μm.
0.56μm
Roughly how large is a bacterial cell?
1μm.
Convert 4.7 cm to μm.
47000μm
first convert to mm
the convert to μm
How would you rearrange the magnification equation to find image size?
image size = magnification x object size
Which of the following are considered ‘eukaryotes’?
Animals
Protoctists
Fungi
Bacteria
Plants
Viruses
animal
protoctists
fungi
plants
what is the idependant variable in the osmosis practical
concentration of the salt or sugar solutions
what is the dependant variable in the osmosis practical
change in mass of the potato pieces
what is the control variable in the osmosis practical
volume of solution, temperature of the solutions, time in the solution
what the osmosis practical
- cut potato into identical cyclinders
- beakers with different sugar solution
- one should be pure water and another should be very concentrated with a few other inbetween
- measure mass of cyclinders before and leave one cyclinder in eahc beaker for 24 hours
- take them out + dry them and weigh again
if cylinders have been drawn in by osmosis: increased in mass
if water has been drawn out they will have a decrease in mass
why do we calculate the percentage change on the osmosis practical
you can comapre the effect of sugar concentration on cyclinders that didnt hav ethe same starting mass
what is the interphase
cell growth and syhthesis of new DNA
what is ctyokinesis
cytoplasm and cell membrane divides to produce two daughter cells
which stage is the biggest part f the cell cycle
the growth and replication
