Cells Flashcards
What are the functions of the nucleus
Control centre of cell through production of mRNA and tRNA and so responsible for protein synthesis/transcription , retain genetic material in the form of chromosomes and manufacture ribosomal RNA and ribosomes, sites of dna replication.
What are the key components of the nucleus and what do they consists of/do
Nuclear envelope (double membrane, controls entry and exit) nuclear pores (allow passage of larger molecules like mRNA) nucleoplasm (jelly material that makes up bulk of nucleus) chromosomes (consist of dna)and nucleoli which makes ribosomal RNA. Has chromatin
What is the function of the double membrane in the nucleus
It controls the entry and exit of materials in nucleus and contains reactions that take place
What is the function of chromatin inside the nucleus
It contains histones and condenses during cell division to become a chromosome
What are the functions of mitochondria
They are the sites of aerobic respiration and they produce ATP
What are the 3 main components of mitochondria and explain them
Double membrane (controls entry & exit of material, the inner folds to from cristae) cristae (provides large surface area for enzymes in respiration) matrix (contains lipids, 70s ribosomes and circular dna that allow mitochondria to produce own proteins) they are the sites of aerobic respiration, shape means short diffusion pathway
What is within and the function of the rough endoplasmic reticulum
Has ribosomes. It’s function is to give large SA for synthesis Of proteins and glycoproteins and give a pathway for transport of proteins
What is the smooth endoplasmic reticulum and what does it do
Sheet like membranes that lack ribosomes. It’s function is to synthesise, store and transport lipids and carbohydrates
What are the functions of the Golgi body
Proteins and lipids produced in the ER are passed through the Golgi apparatus where they are modified (by adding non protein components like carbs) and are labelled so sent to correct destination. They are are then transported out of the cell in Golgi vesicles
The three components of chloroplasts and what they contain/do
Choloplast envelope (highly selective double plasma membrane that controls what exits/enters) grana (stacks of thylakoids that contain chlorophyll) stroma (fluid filled matrix where the 2nd stage of photosynthesis occurs, also contains starch, circular dna, 70s ribosomes)
What are the functions of lysosomes
Hydrolyse material ingested by phagocytic cells, release enzymes to outside of the cell to destroy material, digest worn out organelles so the useful chemicals can be re used. Break down cells after they have died (autolysis)
Describe the structure of lysosomes
Contain lysozymes, enzymes which hydrolyse the cell wall of certain bacteria
Structure and function of ribosomes
Small granules made of 2 subunits found in all cells (either in cytoplasm or RER) 80s in eukaryotic, 70s in prokaryotic, mitochondria and chloroplasts (smaller). Subunits contain ribosomal rNA and protein. They are the site of protein synthesis
The structure of the cell wall
A number of polysaccharides such as cellulose ( have considerable strength) a thin middle lamella which marks boundary between walls
The function of a cell wall
Provide mechanical strength to prevent cell from bursting under pressure from osmosis, give strength to plant as a whole and to allow water to pass along it
The structure of the vacuole
Fluid filled sack bound by the tonoplast membrane. It contains mineral salts, sugars, amino acids, wastes and pigments
Functions of the vacuole
Support plants by making cells turgid, sugars and amino acids can act as temporary food store, pigments may colour petals to attract pollinating insects
How and why do cells become specialised in eukaryotic cells
Different genes are expressed in each type of specialised cell they they can perform specific functions
What may change in a specialised cell
The shape and number of specific organelles
The order of complex cell structures
Specialised cells, tissues, organs and systems
What is the definition of tissue
A group of similar cells that perform a specific function
What are two examples of tissues (one animal one plant)
Epithelial (sheets of cells that line organs like the alveoli in lungs), xylem (transports water and mineral ions)
Organ definition
A combination of tissues that are coordinated to perform a variety of functions
2 examples of organs (one animal, one plant)
The stomach (has muscle to churn, epithelium to protect stomach wall) a leaf (xylem,phloem,spongy mesophyll and palisade mesophyll for photosynthesis)
Organ system definitions
Organs working together as a single unit to perform specific functions
Examples of organ systems in humans
Digestive system (digests and processes food with salivary glands, oesophagus, stomach &other) respiratory system (breathing and gas exchange with trachea, bronchi, lungs) circulatory (heart arteries and veins)
Adaptations of a sperm cell
Contains mitochondria to release energy for the flagellum, tail rotates to propel towards the egg, acrosome in head has digestive enzymes to break down outer layer of egg, head has haploid nucleus
Adaptations of a root hair cell
Root hair to increase surface area so rate of water and ion uptake by osmosis is increased, thinner walls than other plant cells so shorter diffusion distance for water, mitochondria for active transport of mineral ions
How prokaryotic cells differ from eukaryotic
No nucleus, dna not associated with proteins, dna in circular form with plasmids, no membrane bound organelles, 70s ribosomes, cell wall made of meurin, may have capsule
The key structure of bacteria/prokaryotic cells
A cell wall made of murein, many have a capsule, a cell surface membrane, cytoplasm with 70s ribosomes and circular strand dna with plasmids and one or more flagellum
What are viruses
Acellular and non living
Describe the structure of a virus
Very small (20-300nm), their genetic material is in the form of nucleic acids (dna/rna), everything enclosed within capsid which has attachment proteins
