b1 Flashcards
what organelle is the outmost of the cell?
cell wall
what’s the function of the nucleus?
contains genetic material and controls the activities of the cell
what is the function of the cell membrane?
controls what goes in and out of the cell
what’s the function of the cytoplasm?
a gel like substance where most chemical reactions happen. contains enzymes that control these reactions
what’s the function of the mitochondria?
where most of the reactions for respiration take place.
what is the function of the ribosomes?
where proteins are made in the cell
(protein synthesis)
what is the function of the vacuole?
contains cell sap, a weak solution of sugar and salts
what’s the function of the cell wall
a rigid structure made of cellulose. supports and strengthens the cell. algae cells (e.g seaweed) also have this.
what is the function of the chloroplasts
where photosynthesis occurs which makes food for the plant. contains green substance called chlorophyll
what is a specialised cell
a specialised cell has structural adaptations that help it to o carry out a specific function
what is magnification?
the number of times bigger the image size is compared to the real size.
what is resolution
the ability to distinguish between two points i.e how detailed the image is.
which organelles are only in plant cells.
chloroplasts, vacuole, cell wall
how do you calculate magnification?
image size / actual size
how do you calculate image size
magnification x actual size
how do you calculate actual size?
image size/ magnification
functions and adaptations of a muscle cell
function is to contract and relax to allow movement
adaptation is many mitochondria to provide energy for it
functions and adaptations of a nerve cell
function is to send electrical impulses to coordinate responses in the nervous system
adaptations- large surface area to receive impulses
function and adaptation of root hair cell
function- absorb water and minerals from soil
adaptation- long extension provides large surface area to increase the rate of absorption. thin cell wall for a shorter distance for water absorption
lots of mitochondria
function and adaptation of xylem cell
function - transports water and mineral ions from root upwards
adaptation - walls are thickened which chemical called lignin which provides strength and support
function and adaptation of phloem cell
function - transports amino acid es and food substances such as glucose uo and down the cell
adaptation - has sieve plates at end walls so cytoplasm connects between cells and living cells
function and adaptations of sperm cell
function- carry paternal genetic information
adaptations - large nucleus to store dna
an acrosome in the head- contains digestive enzymes to break down egg to reach nucleus. tail to swim. mitochondria in the neck for energy to swim
what’s the magnification of an electron microscope
x500,000
what’s the magnification of a light microscope
x2000
what’s the resolution of an electron microscope?
0.2 nm
what’s the resolution of a light microscope
200 nm
what’s the size of an electron microscope in comparison to a light microscope
a light microscope is portable
electron is large and fixed
what microscope can you view dead only with
electron
how do you calculate total magnification
eyepiece lens x objective lens
( the objective lens is usually ten and the eyepiece lens changes)
why is it important to use forceps gently when placing down the specimen
to prevent air bubbles and fingerprints
on a light microscope, what do you place your specimen on
the stage
what is beneath the stage on a light microscope?
the light source
which knob on a light microscope is larger: coarse focus of fine focus?
coarse focus
steps for using the light microscope
(six steps)
- turn to the lowest objective lens and place specimen slide on stage and secure with stage clips.
- adjust light source so it passes through the slide
- move stage as close to lens as possible, slide must not touch lens
- look through eyepiece and focus using the coarse focus first so slide moves away from the lens
- use fine focus to make it clearer
- select eyepiece lens and objective lens to reach your total (multiply them together)
- refocus slide using focussing knob
name two prokaryotic cells
bacteria and archaea
give a difference between prokaryotic and eukaryotic cell
prokaryotic has plasmid
which microscope is needed to see ribosomes and mitochondria?
electron
how are the lungs adapted for efficient exchange of gases?
many alveoli - large surface area
thin capillaries- shorter diffusion path
good blood supply - maintain a concentration gradient
well ventilated - bring in fresh oxygen
name the chemical which genetic material is made from
DNA
explain how a transplant of bone marrow cells can help to treat medical conditions
bone marrow cells can give rise to other types of cells through differentiation so will cure diseases where new cells are needed
how is the structure of an artery related to its function
thicker muscle walls to push blood around the body
how does haemoglobin and a lack of nucleus help a red blood cell
no nucleus - more space for oxygen
haemoglobin - transport oxygen around the body
question one on b1 pack ( osmosis )
for tube 1 , it expands and gains water because the concentration of water is less than its surroundings
for tube 2, it gets floppy as it loses water because the concentration of water is greater than its surroundings
the rate that nitrate ions are absorbed by roots increases when oxygen is added. how does this show how nitrate ions are absorbed?
more nitrate ions are absorbed in the presence of oxygen which suggests they are absorbed by active transport which requires energy from respiration. some nitrate ions are absorbed by diffusion
what is the chloroplast
site of photosynthesis
cell wall function
supports the cell
keeps the shape
keeps it rigid
vacuole function
acts as a reservoir for water
explain why sexual reproduction could lead to a new variety of plant
fertilisation occurs so leading to the mixing of genetic information and one copy of each gene from each parent can cause variation
what’s the difference between a red blood cell and a plant cell
red blood cell has no nucleus, no cell wall, no chloroplast no chlorophyll, no vacuole. red blood cell has haemoglobin and is much smaller then plant cell.
both have cell membrane, cytoplasm and pigments (different pigments)
a red blood cell and a plant cell are placed in water. the red blood cell swells and bursts. why
water enters the cell by osmosis
the plant cell has a cell wall which prevents it from bursting. red blood cell has no cell wall so it swells and bursts
a student investigates bacteria in petri dishes how could they improve the experiment
repeat and eliminate anomalies
repeat and calculate a mean
use different types of bacteria
name two similarities between prokaryotic and eukaryotic cells
cytoplasm
membrane
name three differences between prokaryotes and eukaryotes
prokaryotes are smaller and have plasmids has no nucleus
explain the 3 stages of mitosis
STAGE ONE : dna replicates. sub-cellular structures increase in number.
STAGE TWO : one of each chromosome is pulled to each end of the cell
STAGE THREE: the cytoplasm and cell membrane divide to form two genetically identical daughter cells
how many micrometers in a millimetre
1000
how many micrometers in a mm
1000
why would bar graphs be drawn instead of line graphs
if data is categoric
why is iodine solution used when preparing an onion slide?
it binds to starch in plant cells
it is a stain so it makes cellular structures easier to see
what stain should be used to see the nucleus of a cheek cell?
methylene blue
