Bio Flashcards
What is the formula for magnification,actual size and image size
Image size
Actual size x Magnification
What are plant cell walls made of
Cellulose
Bacteria peptidoglycan(murein)
What is diffusion
The net movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient until an equilibrium is reached.
What factors affect diffusion
Surface area,temperature and concentration gradient
How does surface are affect diffusion
The larger the surface area, the faster the rate of diffusion as the have more area to diffuse across
How does temperature affect diffusion
It increases it by giving the particles more kinetic energy increasing their speed and helping the overcome the activation energy
How does the concentration gradient affect diffusion
Increases it by more particles will randomly move from the area of high conevtration to low concentration
What is diffusion used for in living organisms
Used to transfer substances and allow different processes
What substances are moved in and out of cells
Gases,simple sugars, water and waste products
What is osmosis
The net movement of water particles through a partially permeable membrane from a less concentrated solution to a more concentrated solution
What is active transport
The movement of particles from an area of lower concentration to higher concentration against the concentration gradient
What happens to water molecules when they enter a plant cell
It would cause the vacuole to either swell or shrivel
What happens when animal cell are placed in a dilute solution
They will either lose or take in water and therefore shrivel or burst
What is it called when an animal cell loses water and shrivels
Crenation
What is it called when animal cells take in too much water and bursts
Lysis
What causes a high/low turgor pressure in a plant cell
Water moving in and out of a plant cell swelling/shrivelling the vacuole
What does high turgor pressure cause
The cell becoming turgid and causing the plant to wilt
What does low turgor pressure cause
The cell to be flaccid causing the plant to be rigid
What is larger eukaryotes or prokaryotes
Eukaryotes
What sub-cellular structures do prokaryotes not include
Mitochondria or chloroplasts
Where is the DNA found in a Prokaryote
It is one molecule that is free in the cytoplasm.
What are plasmids
Additional pieces of DNA that are one or more stirngs
What is the shape of a red blood cell and why
They are biconcave discs that increase the surface area of the cell. This increases diffusion
What are the features of red blood cells
Biconcave disc shape
Lots of haemaglobin
No nucleus
Is there only one type of white blood cell
No
What are what are some of the different functions of white blood cells
Attacking invading micro-organisms directly,producing antibodies
What are ciliated epithelial cells
Cells covered in cilia that line the respiratory system and produce mucus to trap dirt and micro-organisms
What is plasmolysis
A plant cell loses too much water and the cytoplasm shrinks pulling away the cell membrne from the cell wall
What does the nucleus contain
Information in the form of chromosomes
How many chromosomes do human cells contain
23 pairs of chromsomes
What is a gene
A small part of DNA which makes up the chromosome. It determines a certain characteristic in the organism
What is the cell cycle
The cycle body cells go through to divide into two with the exact same genes with little variation
how many stages are in the cell cycle
3
What is stage 1 of the cell cycle
Replication of the DNA in the nucleus forming two copies of each chromosome
Subcellular stuctures are also produced
This is the longest stage
What is stage 2 of the cell cycle
Mitosis occurs
What is mitosis
When the chromosomes move apart and the nucleus splits in two.
What is stage 3 of the cell cycle
The cell divides in two
What is the name for a fertilised egg cell
The zygote
What are embryos made of
Embryonic stem cells
What is differentiation
The name of the process by which cells become “specialised” for specific jobs
What are embryonic stem cells
Cells made from mitosis at the end of fertilisation that can differentiate into different specialised cells.
Until then, the cells are considered undifferentiated
What happens inside the apical meristem in a plant
Mitosis is constantly occurring so that the plant can grow. All of these cells are undifferentiated.
What are the names of the two vessels inside the vascular cylinder of a plant
The xylem and phloem
What is the purpose of the xylem
It can transport both water and minerals up throughout the plant
What is the purpose of the phloem
It can move food substances(glucose) made from photosynthesis throughout the plant
What are the three main nutrients
Carbohydrates,proteins and lipids(fats)
Why does the body need carbohydrates
They act as fuel/energy that can make other chemical reactions in the body.
This energy can be either short term(simple sugars) or long term(complex carbohydrates)
Why does the body need proteins
It allows for the growth of new cells and the repair of tissue in the body
Why does the body need lipids
They are efficient energy stores and for other animals can be insulation
What does hypertonic mean
When the surrounding solution is more concentrated and the inner solution is more dilute
What does isotonic mean
When both the surrounding and inner solutions are equally concentrated/dilute
What does hypotonic mean
When the surrounding solution is more dilute than the inner solution which is more concentrted
Gametes contain half the amount of genetic material(true or false)
True
How many unpaired chromosomes does the sperm and egg cell have each
23
What are the parts/structures of the ovum/egg cell
Nucleus,cytoplasm and a layer of jelly
Structures of nerve cells
Nucleus,cytoplasm,cell membrane,axon and sheath
What is the axon in a nerve cell and what is it insulated in
It is the main body of the nerve cell
It is insulated in myelin to prevent electrical signals from being lost
Why do muscles look straped or striated
The muscle is made of thin filaments that can slide over eachother
What helps muscles contract
Special proteins
How are viruses different to other protists
-They are very small
-they invade cell and reproduce in them(damaging the cells in the process
What are some examples of viruses
Measles,HIV,TMV(tobacco mosaic virus)
Symptoms of measles
Fever and red skin rash
How is measles spread
Through inhalation of droplets from cough and sneezes
How can measles be treated
There is no treatment however we can only prevent the spread through isolation
What are the symptoms of HIV
Mild,flu-like illness
How does the HIV virus harm the body
Attacks the immune system and remains hidden until it is compromised
What can the HIV virus lead to
AIDS
How is HIV spread
It can be spread through bodily fluids such as blood,needles and more
How is HIV treated
It cant be treated however it can be prevented through the use of condoms,not sharing needles and such
How is TMV spread
It is spread through contact between healthy and infected plants with insects as the vector
What is a vector
Organisms that transmit diseases
How is TMV treated
It cannot be treated but its spread can be prevented by good field hygiene and pest control
What are bacteria
Small,single-celled organisms that are very different to plant and animal cells
What are types of bacteria
Salmonella,gonorrhoea
What is salmonella and where are they found
Salmonella is a bacteria that lives in the guts of many different animals
What are the symptoms of salmonella
Fever,abdominal cramps,diarrhoea,vomiting
How can salmonella be prevented
Keeping raw chicken away from food,being washed,washing hands, cooking chicken thoroughly
What is gonorrhoea
An STD
How is gonorrhoea spread
Unprotected sexual contact with an infected person
What are the short term symptoms of gonorrhoea
Thick yellow/green discharge
Pain from urination
What are the long term symptoms of gonorrhoea
Long term pelvic pain,infertility,ectopic pregnancies
Can gonorrhoea be treated
It can be with antibiotics
What are protists
Small,single-celled organisms that are relatively rare pathogens
What is an example of a fungal disease
Rose black spot
What are some symptoms of rose black spot infection
Purple or black spots on leaves
Yellow and falling leaves
How is rose black spot spread
The spores are spread by the wind and are spread between plants through insects
Rose black spot can be prevent by
-removing and burning infected leaves
-using fungicides
-breed more resistant plants
What are the symptoms of malaria
Recurrent episodes of fever and shaking
How can the spread of malaria be contorlled
-use insecticide
-cover or spray water to reduce the amount of vector
-use insect nets
