Cells Flashcards
What type of cell is a potato cell
Root hair cell
As organisms get larger does their surface area to volume ratio increase or decrease
Decreases
E.g a cow has a small surface area to volume ratio but a mushroom has a large surface area to volume ratio
What does a small surface area to volume ratio mean
Less surface area compared to their volume
What does a high/ big surface area to volume ratio mean
More surface area available in comparison to their volume
Do bacteria have a low or high surface area to volume ratio
High
(Lots of surface area compared to their volume)
Do cows have a high or low surface area to volume ratio
Low
Not much surface area in comparison to volume
Which is a larger surface area to volume ratio 6:1 or 2:1
6:1 as there is more surface area (6) compared to volume (1)
Why can’t humans rely on diffusion for all of our needs but bacteria can
Bacteria have high surface area to volume ratio so can rely on diffusion across their surface to exchange everything they need
Humans have a low surface area to volume ratio so diffusion across our surface alone isn’t enough to exchange everything we need
True or false, in organisms with a low surface area to volume ratio, the diffusion distance is too large to meet the demands of the cell/ organism
True e.g humans
(That’s why we have transport systems inside us e.g respiratory system)
Why do organisms with a higher surface area to volume ratio have a greater metabolic rate
More surface area to lose heat from so will lose heat more quickly
Will need greater rate of respiration (part of metabolism) to generate heat to keep itself warm
What is the relative size of a bacterial cell
0.2-2 micrometres
What is the relative size of an animal cell
10-30 micrometres
What is the relative size of a plant cell
10-100 micrometres
Which tend to be bigger plant or animal cells
Plant
List all parts of prokaryotic (bacterial) cell
Slime capsule, cell wall, cell membrane, flagella, cytoplasm, plasmid, ribosomes, genetic material
Where is DNA found in a prokaryotic (bacterial) cell
Plasmid
(Small loop of DNA)
Where is genetic information found in a prokaryotic (bacterial) cell
Genetic material
Plasmid (small loop of DNA)
True or false, bacterial cells contain mitochondria and ribosomes
False
They only contain ribosomes
3x Sperm cell adaptations
Long tail- helps it swim through water to reach egg cell and fertilise it
Middle section- full of mitochondria to release energy that it needs to swim to reach egg cell
Acrosome- stores digestive enzymes to break down outer layers of egg
Purpose of acrosome in sperm cell
Contains digestive enzymes to break down outer layer of egg cell
Purpose of middle section in sperm cell
Contains lots of mitochondria to release lots of energy needed to swim and reach egg cell
2x adaptations of nerve cell
Nerve endings (synapses) contain lots of mitochondria- provide energy to make transmitter chemicals which then pass impulses to other cells
Branched endings (dendrites)- make connections with other neurones and effectors
Fatty sheath- insulates nerve cell to speed up impulses
Why do synapses (nerve endings of nerve cells) contain lots of mitochondria
Release energy needed to make transmitter chemicals which then pass impulses to other cells
Purpose of branched endings (dendrites) of nerve cells
Send electrical impulses to neurones and effectors (make connections to other nerve cells)
2x adaptations of muscle cells
Contain lots of mitochondria to release energy for contraction
Contain protein fibres- contract and make cell shorter
Which type of stem cell In humans (+ meristem cells) can differentiate into any type of cell
Embryonic
True or false, meristem cells can differentiate into any type of cell at any point in their lifetime and can re differentiate
True
Difference in resolution between light and electron microscope
Electron microscope has higher resolution
Why do red blood cells have a biconcave disc shape
Increase surface area to volume ratio (maximise surface area) for more space for Haemoglobin to bind to as much oxygen as possible
Magnification=
Image/ actual size
What part of root hair cells gives it large surface area
Long projection
High resolution of microscope meaning
Can easily distinguish between 2 points
True or false, binary fission is a type of asexual reproduction
True
(In prokaryotic cells)
3 factors affecting rate of diffusion
Surface area
Temperature
Concentration gradient
How to calculate number of bacteria in population
Starting number of bacteria x 2 to the power of number of divisions
3 things microorganisms need to grow
Food, warmth, oxygen
Describe the aseptic technique (growing bacteria without contamination)
1) disinfect work surface and hands
2) flame loop and rim/ mouth of containers (if using glass)
3) don’t put lids on surfaces
4) only open Petri dish when necessary
5) use sterile discs
6) Don’t seal whole way round
7) incubate upside down to avoid condensation
How fish gills are adapted for effective gas exchange
Made up of stacks of filament
Large surface area to increase rate of diffusion
Good blood supply
Which types of cell transport require partially permeable membrane
Active transport
Osmosis
True or false diffusion must have a partially permeable membrane
False
It can but doesn’t need to
What is a stem cell
Undifferentiated cell
Name for top lens on miscroscope
Eye piece lens
(Because your eye looks through it)
One example of active transport in humans
Glucose from blood into small instestine
Describe process of mitosis
DNA replicates (each chromosome becomes a double strand), one set of chromosomes pulled to each end of cell, nucleus divides, number of sub cellular structures increases, cytoplasm and cell membrane divide, produces 2 identical daughter cells
Describe process of meiosis
In parent cell chromosomes make identical copies of themself, sections of DNA get swapped, pairs of chromosomes divide twice forming 4 non- identical cells (gametes)
Compare chromosomes to genes to DNA
DNA is a polymer
Small section of DNA is a gene
Genes are contained inside chromosomes
What is a gene
Small section of DNA
For microscopy RPA which objective lens do we usually start with
Lowest power
How can embryonic stem cells be used to treat diabetes
Extract embryonic stem cells from embryo, grow them in a lab, stimulate them to form pancreatic sell’s which produce insulin and inject theses cells into the patient
2 negatives of embryonic stem cells
Risk of transferring viral infection
Ethical issues
3 reasons adult stem cells are better than embryonic
Not unethical
No rejection (white blood cells seeing them as foreign and trying to destroy them) as taken from patient themself
Easier to get hold of
