Biology - CELLS

Name 5 components of the plasma membrane

Phospholipids, cholesterol, intrinsic proteins, glycoproteins, glycolipids

What gives the cell membrane structure?

cholesterol

Name proteins that span the membrane

channel proteins

what proteins act as receptors and transport substances into a cell?

carrier proteins

describe the arrangement of phospholipids in a cell membrane

bilayer

which 2 cell organelles contain DNA

chloroplasts, mitochondria

what are the inner foldings of the mitochondria called

cristae

what are chloroplasts filled with

stroma

name the membrane inside a chloroplast

thylakoid membrane

what are grana in a chloroplast

stacks of thylakoid membranes

what are lamella in a chloroplast

connecting pieces of membrane between grana

name the 2 types of electron microscope

scanning and transmission

what do you use to calibrate a light microscope

stage graticule

give 3 adaptations of an RBC

no nucleus, biconcave, haemoglobin

give an adaptation of a cell producing hormones

many RER, golgi bodies and mitochondria

give an adaptation of a sperm cell

acrosome containing enzymes, lots of mitochondria ,flagellum

as a cell gets larger, what happens to its SA:V ratio

gets smaller

what is a tumour

a mass of tissue undergoing uncontrolled cell division

Give 3 treatments of cancer

radiotherapy, chemotherapy, immunotherapy

how do you calculate magnification of an image

image size/actual size

what organelle contains genetic info

nucleus

what organelle is found in large numbers in active cells

mitochondria

what organelle is used by phagocytes to digest pathogens

lysosomes

what organelle carries out protein synthesis

ribosomes

what does RER do

folding and modification of proteins

what does SER do

synthesis of lipids

what does the golgi body do ?

transporting, modifying and packaging proteins and lipids into vesicles for delivery to target destination

what is the function of a cell wall in plant cells

structure, support

what is a tissue

a group of the same type of cell working together to perform a specific function

what is an organ

structure made of different types of tissues working together to perform a specific function

what type of organelles do prokaryotic cells not have

membrane bound organelles

describe the DNA in a prokaryote

single stranded, no histones, circular

name 3 structures that make up a virus

protein coat/capsid , DNA/RNA, (sometimes lipid envelope), attachment proteins

what can be seen in an electron microscope but not an optical microscope

small cell organelles

what can be observed with an optical microscope but not an electron microscope

colour, living structures

why does an electron microscope have a better resolution than an optical microscope

electron stream has a smaller wavelength

what laboratory process can be used to separate organelles

cell fractionation

what conditions are required for cell fractionation

isotonic, ice cold, pH buffered

why does it need to be isotonic for cell fractionation

prevent organelles bursting/shrinking due to osmosis

why does it need to be ice cold for cell fractionation

reduce enzyme activity that could break down organelles

why does it need to be buffered for cell fractionation

so pH doesn’t fluctuate so proteins don’t denature

what is the order of organelles removed in ultracentrifugation (heaviest first)

nucleus, chloroplast, mitochondria, lysosomes, ER, ribosomes

what stage of the cell cycle does cell replication occur in

Interphase (S phase)

name the 2 parts of a chromosome

histone proteins and DNA

what holds sister chromatids together

centromeres

name the stages of mitosis in order

prophase, metaphase, anaphase, telophase

how can you tell if a cell is undergoing mitosis underneath the microscope

chromosomes are condensed

during which phase do chromosomes line up along the equator of the cell

metaphase

during what stage are the sister chromatids separated

anaphase

what part of the cell is needed for anaphase to happen

spindle fibres, centrosomes

what happens during prophase

chromosomes condense

what is bacteria cell cycle called

binary fission

what are the 2 steps of binary fission

DNA replication - circular DNA and plasmid DNA replicates, cellular division - cytoplasm divides into 2 daughter cells. Each daughter cell has 1 copy of circular DNA and varying numbers of copies of plasmids

what are the structural features of the nucleus

surrounded by the nuclear envelope which has nuclear pores , contains chromosomes consisting of protein bound linear DNA

what is the function of the cell surface membrane

partially permeable so controls the exchange between the cell and the environment

what are the 2 main features of a virus differentiating them from life on earth

acellular and non living

what 3 organelles do plant cells have that animal cells don’t

permanent vacuole,cell wall, chloroplasts

what is the difference between ribosomes in prokaryotic and eukaryotic cells

prokaryotic cells have smaller 70s ribosomes, eukaryotic have bigger 80s

what stain can be used to colour starch granules in plant cells

iodine dissolved in potassium iodide

why do cells need to divide

repair of damaged tissues, growth, asexual reproduction

what are the 2 types of cell division in eukaryotic cells

mitosis and meiosis

what are the products of mitosis

2 daughter cells that carry the same number of chromosomes as the parent cell and identical copies of their DNA

why is a cell in interphase not ‘resting’

cell is actively synthesising biochemical molecules and organelles, increasing energy reserves, and growing

during which phases of mitosis does the nuclear envelope a) disintegrate and b)reappear

a)prophase

b)telophase

describe what happens to a) spindle fibres and b)chromosomes during anaphase

a) spindle fibres contract

b)chromatids of each chromosome are pulled to opposite poles of the cell

describe the appearance of the cell during telophase

cell contains 2 distinct nuclei

in a cell undergoing mitosis, what happens during cytokinesis

parent cell divides to form 2 genetically identical daughter cells

list the 3 stages of interphase in order

gap phase 1 (G1) , synthesis phase (S) , gap phase 2 (G2)

during which stage in interphase does the formation of organelles and an increase in energy reserves take place

growth phase 2 (G2)

how is mitotic index calculated

number of dividing cells in a population/ total number of cells in a population

would you expect cells in a root tip to have high or low mitotic index and why

high - root tip area of rapid cell division

What is the function of vacuoles?

storage of water and nutrients

How do viruses infect cells?

hijack host cellular machinery

What is the role of the capsid?

protein coat surrounding genetic material

Describe the purpose of homogenisation

breaks cells to release contents

what is the supernatant

liquid above sediment after centrifugation